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Roger Cotes
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Roger Cotes FRS (10 July 1682 – 5 June 1716) was an English mathematician, known for working closely with Isaac Newton by proofreading the second edition of his famous book, the Principia, before publication. He also devised the quadrature formulas known as Newton–Cotes formulas, which originated from Newton's research,[4] and made a geometric argument that can be interpreted as a logarithmic version of Euler's formula.[5] He was the first Plumian Professor at Cambridge University from 1707 until his death.
Key Information
Early life
[edit]Cotes was born in Burbage, Leicestershire. His parents were Robert, the rector of Burbage, and his wife, Grace, née Farmer. Roger had an elder brother, Anthony (born 1681), and a younger sister, Susanna (born 1683), both of whom died young. At first Roger attended Leicester School, where his mathematical talent was recognised. His aunt Hannah had married Rev. John Smith, and Smith took on the role of tutor to encourage Roger's talent. The Smiths' son, Robert Smith, became a close associate of Roger Cotes throughout his life. Cotes later studied at St Paul's School in London and entered Trinity College, Cambridge, in 1699.[6] He graduated BA in 1702 and MA in 1706.[2]
Astronomy
[edit]Roger Cotes's contributions to modern computational methods lie heavily in the fields of astronomy and mathematics. Cotes began his educational career with a focus on astronomy. He became a fellow of Trinity College in 1707, and at age 26 he became the first Plumian Professor of Astronomy and Experimental Philosophy. On his appointment to professor, he opened a subscription list in an effort to provide an observatory for Trinity. Unfortunately, the observatory was still unfinished when Cotes died, and was demolished in 1797.[2]
In correspondence with Isaac Newton, Cotes designed a heliostat telescope with a mirror revolving by clockwork.[7][8] He recomputed the solar and planetary tables of Giovanni Domenico Cassini and John Flamsteed, and he intended to create tables of the moon's motion, based on Newtonian principles.[citation needed] Finally, in 1707 he formed a school of physical sciences at Trinity in partnership with William Whiston.[2]
The Principia
[edit]From 1709 to 1713, Cotes became heavily involved with the second edition of Newton's Principia, a book that explained Newton's theory of universal gravitation. The first edition of Principia had only a few copies printed and was in need of revision to include Newton's works and principles of lunar and planetary theory.[2] Newton at first had a casual approach to the revision, since he had all but given up scientific work.[citation needed] However, through the vigorous passion displayed by Cotes, Newton's scientific hunger was once again reignited.[citation needed] The two spent nearly three and half years collaborating on the work, in which they fully deduce, from Newton's laws of motion, the theory of the moon, the equinoxes, and the orbits of comets. Only 750 copies of the second edition were printed[2] although pirated copies from Amsterdam were also distributed to meet the demand for the work.[citation needed] As a reward to Cotes, he was given a share of the profits and 12 copies of his own.[citation needed] Cotes's original contribution to the work was a preface which supported the scientific superiority of Newton's principles over the then popular vortex theory of gravity advocated by René Descartes. Cotes concluded that the Newton's law of gravitation was confirmed by observation of celestial phenomena that were inconsistent with the vortex theory.[2]
Mathematics
[edit]Cotes's major original work was in mathematics, especially in the fields of integral calculus, logarithms, and numerical analysis. He published only one scientific paper in his lifetime, titled Logometria, in which he successfully constructs the logarithmic spiral.[9][10] After his death, many of Cotes's mathematical papers were edited by his cousin Robert Smith and published in a book, Harmonia mensurarum.[2][11] Cotes's additional works were later published in Thomas Simpson's The Doctrine and Application of Fluxions.[9] Although Cotes's style was somewhat obscure, his systematic approach to integration and mathematical theory was highly regarded by his peers.[citation needed] Cotes discovered an important theorem on the n-th roots of unity,[12] foresaw the method of least squares,[13] and discovered a method for integrating rational fractions with binomial denominators.[9][14] He was also praised for his efforts in numerical methods, especially in interpolation methods and his table construction techniques.[9] He was regarded as one of the few British mathematicians capable of following the powerful work of Sir Isaac Newton.[citation needed]
Death and assessment
[edit]Cotes died from a violent fever in Cambridge in 1716 at the early age of 33. Isaac Newton remarked, "If he had lived we would have known something."[2]
See also
[edit]References
[edit]- ^ Gowing 2002, p. 5.
- ^ a b c d e f g h i Meli (2004)
- ^ Rusnock (2004) "Jurin, James (bap. 1684, d. 1750)", Oxford Dictionary of National Biography, Oxford University Press, retrieved 6 September 2007 (subscription, Wikipedia Library access or UK public library membership required)
- ^ Iliffe, Rob; Smith, George E., eds. (2016). The Cambridge Companion to Newton (2nd ed.). Cambridge University Press. p. 411. doi:10.1017/cco9781139058568. ISBN 978-1-139-05856-8.
- ^ Cotes wrote: "Nam si quadrantis circuli quilibet arcus, radio CE descriptus, sinun habeat CX sinumque complementi ad quadrantem XE; sumendo radium CE pro Modulo, arcus erit rationis inter & CE mensura ducta in ." (Thus if any arc of a quadrant of a circle, described by the radius CE, has sinus CX and sinus of the complement to the quadrant XE; taking the radius CE as modulus, the arc will be the measure of the ratio between & CE multiplied by .) That is, consider a circle having center E (at the origin of the (x, y) plane) and radius CE. Consider an angle θ with its vertex at E having the positive x-axis as one side and a radius CE as the other side. The perpendicular from the point C on the circle to the x-axis is the "sinus" CX; the line between the circle's center E and the point X at the foot of the perpendicular is XE, which is the "sinus of the complement to the quadrant" or "cosinus". The ratio between and CE is thus . In Cotes' terminology, the "measure" of a quantity is its natural logarithm, and the "modulus" is a conversion factor that transforms a measure of angle into circular arc length (here, the modulus is the radius (CE) of the circle). According to Cotes, the product of the modulus and the measure (logarithm) of the ratio, when multiplied by , equals the length of the circular arc subtended by θ, which for any angle measured in radians is CE • θ. Thus, . This equation has the wrong sign: the factor of should be on the right side of the equation, not the left. If this change is made, then, after dividing both sides by CE and exponentiating both sides, the result is: , which is Euler's formula.
See:- Roger Cotes (1714) "Logometria," Philosophical Transactions of the Royal Society of London, 29 (338) : 5-45; see especially page 32. Available on-line at: Hathi Trust
- Roger Cotes with Robert Smith, ed., Harmonia mensurarum … (Cambridge, England: 1722), chapter: "Logometria", p. 28.
- ^ "Cotes, Roger (CTS699R)". A Cambridge Alumni Database. University of Cambridge.
- ^ Edleston, J., ed. (1850) Correspondence of Sir Isaac Newton and Professor Cotes, … (London, England: John W. Parker), "Letter XCVIII. Cotes to John Smith." (1708 February 10), pp. 197–200.
- ^ Kaw, Autar (1 January 2003). "cotes - A Historical Anecdote". mathforcollege.com. Retrieved 12 December 2017.
- ^ a b c d O'Connor & Robertson (2005)
- ^ In Logometria, Cotes evaluated e, the base of natural logarithms, to 12 decimal places. See: Roger Cotes (1714) "Logometria," Philosophical Transactions of the Royal Society of London, 29 (338) : 5-45; see especially the bottom of page 10. From page 10: "Porro eadem ratio est inter 2,718281828459 &c et 1, … " (Furthermore, the same ratio is between 2.718281828459… and 1, … )
- ^ Harmonia mensurarum contains a chapter of comments on Cotes' work by Robert Smith. On page 95, Smith gives the value of 1 radian for the first time. See: Roger Cotes with Robert Smith, ed., Harmonia mensurarum … (Cambridge, England: 1722), chapter: Editoris notæ ad Harmoniam mensurarum, top of page 95. From page 95: After stating that 180° corresponds to a length of π (3.14159…) along a unit circle (i.e., π radians), Smith writes: "Unde Modulus Canonis Trigonometrici prodibit 57.2957795130 &c. " (Whence the conversion factor of trigonometric measure, 57.2957795130… [degrees per radian], will appear.)
- ^ Roger Cotes with Robert Smith, ed., Harmonia mensurarum … (Cambridge, England: 1722), chapter: "Theoremata tum logometrica tum triogonometrica datarum fluxionum fluentes exhibentia, per methodum mensurarum ulterius extensam" (Theorems, some logorithmic, some trigonometric, which yield the fluents of given fluxions by the method of measures further developed), pages 113-114.
- ^ Roger Cotes with Robert Smith, ed., Harmonia mensurarum … (Cambridge, England: 1722), chapter: "Aestimatio errorum in mixta mathesis per variationes partium trianguli plani et sphaerici" Harmonia mensurarum ... , pages 1-22, see especially page 22. From page 22: "Sit p locus Objecti alicujus ex Observatione prima definitus, … ejus loco tutissime haberi potest." (Let p be the location of some object defined by observation, q, r, s, the locations of the same object from subsequent observations. Let there also be weights P, Q, R, S reciprocally proportional to the displacements that may arise from the errors in the single observations, and that are given from the given limits of error; and the weights P, Q, R, S are conceived as being placed at p, q, r, s, and their center of gravity Z is found: I say the point Z is the most probable location of the object, and may be most safely had for its true place. [Ronald Gowing, 1983, p. 107])
- ^ Cotes presented his method in a letter to William Jones, dated 5 May 1716. An excerpt from the letter which discusses the method was published in: [Anon.] (1722), Book review: "An account of a book, intitled, Harmonia Mensurarum, … ," Philosophical Transactions of the Royal Society of London, 32 : 139-150 ; see pages 146-148.
Sources
[edit]- [Anon.] . Encyclopædia Britannica. Vol. 7 (11th ed.). 1911.
- Cohen, I. B. (1971). Introduction to Newton's "Principia". Harvard: Harvard University Press. ISBN 0-674-46193-2.
- Edleston, J., ed. (1850). Correspondence of Sir Isaac Newton and Professor Cotes. via Internet Archive
- Gowing, R. (2002). Roger Cotes: Natural Philosopher. London: Cambridge University Press. ISBN 0-521-52649-3.
- Koyré, A. (1965). Newtonian Studies. London: Chapman & Hall. pp. 273–82. ISBN 0-412-42300-6.
- Price, D. J. (1952). "The early observatory instruments of Trinity College, Cambridge". Annals of Science. 8: 1–12. doi:10.1080/00033795200200012.
- Turnbull, H. W.; et al. (1975–1976). The Correspondence of Isaac Newton (7 vols ed.). London: Cambridge University Press. vols.5–6.
- Whitman, A., ed. (1972). Isaac Newton's Philosophiae Naturalis Principia Mathematica: The Third Edition (1726) with Variant Readings. London: Cambridge University Press. pp. 817–26. ISBN 0-521-07960-8.
External links
[edit]- "Harmonia Mensurarum". MathPages. Retrieved 7 September 2007.- A more complete account of Cotes's involvement with Principia, followed by an even more thorough discussion of his mathematical work.
- Roger Cotes at the Mathematics Genealogy Project
- O'Connor, John J.; Robertson, Edmund F., "Roger Cotes", MacTutor History of Mathematics Archive, University of St Andrews
- Meli, D. B. (2004) "Cotes, Roger (1682–1716)", Oxford Dictionary of National Biography, Oxford University Press, retrieved 7 September 2007 (subscription, Wikipedia Library access or UK public library membership required)
Roger Cotes
View on GrokipediaBiography
Early Life and Education
Roger Cotes was born on 10 July 1682 in Burbage, Leicestershire, England, the son of Robert Cotes, the local rector, and his wife Grace Farmer from nearby Barwell.[1] He had an older brother named Anthony and a younger sister, Susanna.[1] His family background in the clergy provided a stable environment, though little is documented about his immediate childhood beyond his early intellectual promise. Cotes received his initial education at Leicester School, where his teachers recognized his exceptional mathematical talent by the age of twelve.[1][5] At this young age, his uncle, the Reverend John Smith, a fellow of Queens' College, Cambridge, arranged for him to transfer to the more prestigious St Paul's School in London.[1] There, under his uncle's tutelage, Cotes engaged in a lively correspondence on mathematical topics, further honing his skills in arithmetic and geometry.[1] In 1699, at the age of sixteen, Cotes matriculated as a pensioner at Trinity College, Cambridge, on 6 April.[1] He excelled in his studies, graduating with a Bachelor of Arts degree in 1702.[1] By 1705, he had been elected a minor fellow of the college, a testament to his burgeoning reputation among contemporaries.[5]Academic Career
As a fellow of Trinity College, Cotes served as a tutor to the sons of the Marquis (later Duke) of Kent, demonstrating his rising reputation within the university. In 1706, Cotes received his Master of Arts degree and was appointed the inaugural Plumian Professor of Astronomy and Experimental Philosophy, a position endowed by Dr. Thomas Plume and nominated by university authorities in January of that year, with formal election on 16 October 1707.[1] In this role, he established an observatory above the King's Gate at Cambridge and resided there, focusing on astronomical observations and computations to advance the professorship's mandate.[6] His appointment at age 24 highlighted his early promise in astronomy and mathematics, and he held the position until his death.[7] Cotes was elected a Fellow of the Royal Society on 30 November 1711, recognizing his scholarly contributions.[1] He took holy orders, being ordained deacon on 30 March 1713 and priest on 31 May 1713, aligning with expectations for Cambridge fellows of the era.[1] Cotes died on 5 June 1716 at age 33, likely from typhus, and was buried in Trinity College Chapel; his cousin Robert Smith succeeded him as Plumian Professor.[6]Death
Roger Cotes died on 5 June 1716 in Cambridge, England, at the age of 33, succumbing to a fever accompanied by violent diarrhoea and constant delirium.[1] He was buried four days later in the chapel of Trinity College, Cambridge, where he had served as a fellow and professor.[1] His sudden passing deeply affected his contemporaries, particularly Isaac Newton, with whom Cotes had collaborated closely. Newton reportedly lamented, "If he had lived, we might have known something," underscoring the profound loss of Cotes' promising contributions to mathematics and astronomy.[1] At the time of his death, Cotes left behind a substantial collection of unpublished manuscripts, which were later edited and published posthumously as Harmonia Mensurarum in 1722.[1]Astronomical Work
Plumian Professorship
The Plumian Professorship of Astronomy and Experimental Philosophy was established at the University of Cambridge by the bequest of Thomas Plume, Archdeacon of Rochester, who died in 1704 and allocated nearly £2,000 to endow a chair dedicated to advancing astronomical study and instruction.[1] Statutes for the position were drafted by Isaac Newton, John Flamsteed, and John Ellys, with trustees appointed to oversee its administration. Roger Cotes, then aged 23, was nominated in January 1706 and appointed as the inaugural professor, supported by endorsements from Newton, William Whiston, and Richard Bentley, despite opposition from Flamsteed. He was formally elected on 16 October 1707 and held the role until his death in 1716. As Plumian Professor, Cotes was tasked with delivering annual lectures on astronomy and experimental philosophy, maintaining astronomical instruments, and conducting observations to support Newtonian principles in celestial mechanics.[1] His lectures were given from dedicated chambers above the King's Gate at Trinity College, which served as a temporary observatory site. To fulfill these duties, Cotes oversaw the acquisition and calibration of equipment, including designing a transit telescope for precise stellar measurements and collaborating with Newton on a heliostat—a device using a revolving mirror to track the sun steadily. He also initiated a public subscription in 1708 to fund a permanent observatory atop Trinity's Great Gate, though construction remained incomplete at his death and was later demolished in 1797.[8] Cotes' astronomical contributions during his professorship emphasized empirical observation and computational refinement aligned with Newtonian theory. He observed the total solar eclipse of 22 April 1715 from Cambridge, noting the visibility of Mercury, Venus, Mars, and several stars amid the corona, as well as the occultation of three sunspots, and sent a sketch of the corona's appearance to Newton. Halley mentioned these observations in the Philosophical Transactions of the Royal Society.[1] Additionally, he remodeled solar and planetary tables to improve predictive accuracy and planned new lunar tables based on Newtonian principles, though the latter remained unfinished.[8] These efforts, though cut short by his early death, laid groundwork for subsequent Cambridge astronomical work, with his cousin Robert Smith succeeding him in the chair.Observational and Computational Contributions
Upon his appointment as the first Plumian Professor of Astronomy and Experimental Philosophy at the University of Cambridge in 1706, Roger Cotes initiated efforts to establish a dedicated observatory at Trinity College. He successfully solicited subscriptions to fund the project and installed observational instruments above the King's Gate, though the full structure remained incomplete at the time of his death in 1716.[1] In collaboration with Isaac Newton, Cotes designed a specialized heliostat telescope equipped with a mirror that rotated via clockwork mechanism, enabling continuous tracking of the sun for prolonged observations. This instrument facilitated his viewing of the total solar eclipse on 22 April 1715 (Old Style), during which he recorded the visibility of three planets—Mercury, Venus, and Mars—and several stars amid the corona. Cotes documented these phenomena and forwarded a sketch of the solar corona's appearance to Newton, marking one of his few surviving observational records. However, as noted by Edmund Halley, Cotes' observations were hampered by excessive social distractions, causing him to miss the precise timings of the eclipse's onset and conclusion.[1] Cotes also conducted a notable observation of a prominent meteor on 6 March 1716, visible from Cambridge at approximately 7:15 p.m. In a letter to Robert Dannye, he described the event as featuring a bright object with triangular streams of light, converging at a point about 20 degrees from the zenith and roughly 10 degrees east of south, aligned with the prevailing wind direction; the meteor appeared midway between the stars in the heads of Gemini's Castor and Pollux. This account, emphasizing the streams' relative impermanence compared to prior reports, was published posthumously in the Philosophical Transactions of the Royal Society.[9] On the computational front, Cotes undertook significant revisions to existing astronomical tables, recalculating the solar and planetary positions originally compiled by John Flamsteed and Giovanni Domenico Cassini to enhance their accuracy using Newtonian principles. He planned to extend this work by developing new tables for the moon's motion, grounded in gravitational theory, though this project remained unfinished. Additionally, Cotes contributed computational sections on tides, lunar orbits, and cometary trajectories to William Whiston's Astronomical Lectures (1716), applying numerical methods to refine predictions of celestial motions. His posthumously published Harmonia Mensurarum (1722) further advanced astronomical computation through innovations in interpolation, numerical integration, and error estimation, which proved valuable for determining comet orbits and constructing precise ephemerides.[1][5]Editorial Role in Newton's Principia
Collaboration with Newton
In 1708, Richard Bentley, the master of Trinity College, Cambridge, recommended the young Roger Cotes, then the Plumian Professor of Astronomy, to oversee the preparation of a second edition of Isaac Newton's Philosophiæ Naturalis Principia Mathematica, which had become scarce since its initial 1687 publication.[6][10] Newton, initially reluctant, agreed and collaborated closely with Cotes from 1709 to 1713, conducting the work remotely from London while Cotes managed the process in Cambridge.[7] Their partnership involved extensive correspondence, with Cotes proposing numerous revisions to tighten mathematical proofs, clarify arguments, and incorporate Newton's amendments, many of which were accepted without alteration.[10][7] The collaboration focused on substantial textual enhancements, including expansions to the lunar theory and comet sections in Books I and III, as well as revisions to Book II's Section VII to address critiques of the gravitational theory.[11][10] Cotes meticulously proofread the manuscript line by line, ensuring consistency and precision, while Newton provided detailed annotations from his personal copy of the first edition.[7] Despite occasional tensions—such as a 1712 dispute where Newton accused Cotes of overlooking an error in the scholium on resistance, later attributed to Johann Bernoulli—their exchanges remained productive, with Cotes often urging Newton to meet deadlines.[6] Cotes received no financial compensation or formal acknowledgment beyond a portrait of Newton in 1712, and the published edition credits him only in his preface.[7] Cotes's preface to the 1713 edition, published in Cambridge with 750 copies, played a pivotal role in defending Newton's principles against Cartesian vortex theory and Leibnizian criticisms, affirming the law of universal gravitation through lunar orbit data and Kepler's third law.[6][11] It positioned attraction not as an occult cause but as a verifiable mathematical framework, enhancing the work's philosophical authority.[11] Following Cotes's untimely death in 1716 at age 33, Newton reportedly lamented, "If he had lived, we might have known something," underscoring the depth of their intellectual partnership and Cotes's irreplaceable contributions to refining one of the era's foundational scientific texts.[6]Key Edits and Additions
Cotes' editorial work on the second edition of Newton's Philosophiæ Naturalis Principia Mathematica (1713) involved meticulous revisions to enhance mathematical precision, clarify demonstrations, and strengthen arguments against rival theories, achieved through extensive correspondence with Newton spanning 1709 to 1713.[12] He proposed numerous alterations to propositions, scholia, and corollaries, many of which Newton adopted or modified, focusing on empirical grounding and rejection of hypotheses like Cartesian vortices.[12] A prominent addition was Cotes' own preface, which rigorously critiqued Cartesian philosophy and refuted assertions that Newton's theory of attraction invoked occult causes, thereby defending the work's methodological foundations.[11] In it, Cotes emphasized the empirical basis of Newtonian gravity, arguing against vortex theories as inconsistent with observations of planetary and cometary motions.[12] This preface, spanning several pages, served as an intellectual bulwark, influencing readers at Cambridge and beyond by aligning the edition with experimental philosophy.[11] Key structural changes included the addition of the Scholium Generale at the end of Book 3, where Newton incorporated it to underscore the inductive method and dismiss speculative causes for gravity.[12] Cotes also influenced substantial revisions in Book 2, Section 9, where Newton replaced earlier content on pendulum decay with new experiments on vertical fall and projectile motion, explicitly rejecting vortices as incompatible with resistance laws; for instance, Cotes suggested omitting the term "triplicata" in discussions of density ratios, which Newton approved to avoid ambiguity.[12] In Book 3, Cotes' input led to refinements in gravitational arguments, such as adjusting the lunar force to approximately 4.4815 times the solar force in Propositions 36–37, reducing it from the first edition's value to better align with precession data, and extending Proposition 20 with new observations on latitude-dependent surface gravity.[12] He proposed clarifications to Proposition 19, including table adjustments (e.g., hexapeda measurements from 57060 to 57292) and omission of fractions for readability, while Newton added corollaries on centripetal force in related scholia.[12] Additions at the end of Book 3 incorporated comet trajectories based on Halley's computations, enhancing the edition's astronomical scope.[11] Further edits addressed printing errors and demonstrations; for example, in Proposition 15 (Book 2), Cotes recommended adding "et motus corporis cessabit" to describe motion cessation under resistance, which Newton integrated.[12] Cotes also compiled a comprehensive index to aid accessibility, praised by Newton for benefiting non-expert readers.[12] These changes, often debated in letters—such as Cotes' critique of vortices as perturbing orbits—resulted in a more robust text, with Newton defending gravity's inverse-square law through added mathematical proofs.[12] Overall, Cotes' contributions elevated the edition's rigor without altering Newton's core principles, as evidenced by their collaborative exchanges.[12]Mathematical Contributions
Integrals and Logarithms
Roger Cotes made significant advances in the integration of logarithmic functions and related curves during his brief career, particularly through his 1714 paper "Logometria," published in the Philosophical Transactions of the Royal Society. In this work, he developed methods for computing logarithms and integrals using continued fractions and geometric constructions, enabling rational approximations for irrational quantities such as roots. A central result was his exploration of complex logarithms, where he established the relation , linking exponential and trigonometric functions in a form that anticipated Euler's formula by decades. This identity arose from his analysis of circular areas and the "Cotes property of the circle," which facilitated the integration of expressions involving imaginary quantities.[13][1][14] Cotes extended these ideas to the rectification of spirals and other curves, demonstrating that the Archimedean spiral and Apollonius's parabola share the same integral form when rectified. He studied the reciprocal spiral, given by , and rectified the logarithmic curve, connecting these to hyperbolic and elliptic integrals. His approach integrated fluxional calculus with geometric insights, allowing for the evaluation of integrals that represented arc lengths and areas under such curves. These methods improved upon prior work by Halley and de Moivre, emphasizing practical computation for astronomical tables.[1][14][15] In his posthumously published Harmonia Mensurarum (1722), edited by Robert Smith, Cotes provided a systematic treatment of integral calculus, including numerical integration techniques now known as the Newton-Cotes formulas. These formulas approximate definite integrals using polynomial interpolation over equal intervals, with specific cases like the trapezoidal rule and Simpson's rule deriving from his interpolation methods. The work cataloged integrals for 18 classes of algebraic functions, focusing on rational fractions with binomial denominators, and unified analysis with synthesis through angular and rational measures. Cotes's contributions emphasized conceptual unification over exhaustive computation, influencing later developments in quadrature and series expansions.[1][14]Series and Other Advances
Cotes made significant contributions to the development of series expansions in the context of logarithms and transcendental functions. In his posthumously published work Harmonia mensurarum (1722), he derived a continued fraction expansion for the mathematical constant , computing it to several decimal places and noting patterns in the partial quotients forming an arithmetic progression, influencing later work on continued fractions by mathematicians such as Leonhard Euler.[1] Building on series techniques, Cotes employed power series expansions, such as that of , to explore connections between exponential and trigonometric functions. His analysis in Logometria (1714) led to the identity , a logarithmic precursor to Euler's formula , demonstrating the analytic continuation of the natural logarithm to complex arguments through series. This result underscored the periodicity and modular properties of complex exponentials, with the constant emerging as the base via the "modular ratio" in his derivations.[1][16] Beyond series, Cotes advanced numerical methods, particularly interpolation and table construction. In Harmonia mensurarum, he developed techniques for interpolating values of 18 classes of algebraic functions, enabling precise computations for astronomical tables and reducing errors in numerical integration. These methods relied on finite difference approximations akin to early forms of polynomial interpolation series.[1] Cotes also anticipated the method of least squares in error analysis for observations. In his posthumously published Harmonia mensurarum (1722), he proposed minimizing the sum of squared residuals in data fitting, a principle later formalized by Adrien-Marie Legendre and Carl Friedrich Gauss, which became foundational in statistics and computational mathematics.[1] In the theory of equations, Cotes discovered key properties of the th roots of unity. In Harmonia mensurarum, he established a theorem relating these roots to logarithmic spirals in the complex plane, showing that the roots lie on a circle and can be connected by spirals of constant angle, providing geometric insights into their algebraic structure and factorization of . This work bridged algebra, geometry, and analysis, prefiguring modern complex analysis.[1]Legacy and Assessment
Contemporary Recognition
During his lifetime, Roger Cotes received notable academic appointments that reflected the esteem of prominent contemporaries. In 1705, he was elected a Fellow of Trinity College, Cambridge, shortly after completing his studies there. The following year, in January 1706, he was appointed the inaugural Plumian Professor of Astronomy and Experimental Philosophy, a position for which he was strongly recommended by Isaac Newton, William Whiston, and Richard Bentley, despite opposition from John Flamsteed; his formal election to the chair occurred on 16 October 1707.[17][1] Cotes' scholarly contributions also garnered institutional recognition. On 30 November 1711, he was elected a Fellow of the Royal Society, affirming his standing among Britain's leading natural philosophers. His most significant contemporary engagement was editing the second edition of Newton's Philosophiæ Naturalis Principia Mathematica (published 1713), a task that involved extensive correspondence with Newton over four years and demonstrated Cotes' deep mathematical insight; Newton personally gifted him an engraved portrait in 1712 as a token of appreciation, one of the few material acknowledgments Cotes received.[2][17][18] Cotes published only one independent paper during his life, Logometria (1714), in the Philosophical Transactions of the Royal Society, where he advanced methods for computing logarithms and evaluated the base of natural logarithms to 12 decimal places; dedicated to Edmond Halley, it highlighted his innovative approach to integral calculus but received limited immediate attention. Upon Cotes' untimely death at age 33 on 5 June 1716, Newton reportedly remarked, "If he had lived we might have known something," underscoring the high regard in which Newton held his protégé's unrealized potential. Overall, while Cotes enjoyed positions of influence and praise from Newton, his broader mathematical work remained underrecognized among peers during his brief career, overshadowed by his editorial role.[13][19][18]Long-Term Influence
Roger Cotes' editorial work on the second edition of Isaac Newton's Philosophiæ Naturalis Principia Mathematica, published in 1713, significantly amplified the treatise's accessibility and authority, incorporating clarifications, corrections, and prefaces that addressed criticisms and expanded its explanatory power, thereby ensuring its foundational role in classical mechanics for centuries.[1] This edition, prepared during extensive correspondence with Newton, resolved ambiguities in the original text and introduced analytical tools that facilitated broader adoption in European scientific circles, influencing generations of physicists and mathematicians.[1] In numerical analysis, Cotes systematized the quadrature formulas now known as Newton–Cotes methods, which approximate definite integrals using polynomial interpolation over equally spaced points; these include the trapezoidal rule and Simpson's rule, remaining standard tools in computational mathematics and engineering despite limitations for high-degree polynomials.[20] Originating from Newton's earlier ideas but formalized in Cotes' posthumous Harmonia mensurarum (1722), these formulas advanced interpolation techniques and error estimation, particularly in astronomical computations, and continue to underpin modern numerical integration software.[1] Cotes' 1714 derivation of the relation , expressed using the radian measure he introduced, provided an early logarithmic form connecting trigonometric and exponential functions via complex numbers, predating Euler's explicit formula by over three decades.[21] Although receiving limited immediate attention, this insight in his "Logometria" paper influenced the development of complex analysis, with Euler independently developing related logarithmic approaches in his Introductio in analysin infinitorum (1748); the historical significance of Cotes' contribution as a precursor was later highlighted in the late 19th century.[22] Cotes' introduction of the radian—a dimensionless angle unit defined as the arc length subtended by the radius—facilitated these trigonometric-logarithmic links and became the conventional measure in higher mathematics, replacing degrees for calculus and physics applications.[1] His posthumously published Harmonia mensurarum also featured theorems on nth roots of unity and integration methods for rational functions, which informed 18th-century progress in series expansions and table construction for astronomical use, though his early death at age 33 curtailed broader direct influence, as lamented by Newton: "If he had lived, we might have known something."[1] In astronomy, Cotes' contributions to error theory and interpolation in comet orbit calculations, along with his notes on Cotes' spirals describing orbital paths under inverse-cube central force fields, endured in celestial mechanics texts.[1][23]References
- https://en.wikisource.org/wiki/Dictionary_of_National_Biography%2C_1885-1900/Cotes%2C_Roger
- https://en.wikisource.org/wiki/Dictionary_of_National_Biography%2C_1885-1900/Newton%2C_Isaac

