Math 2.0

Special functions Proposition

Derivative of arctangent

Builds on ArctangentDerivative of an inverse functionDerivative of tangent

Statement

The arctangent is differentiable on ℝ\mathbb{R}, and ddxarctan⁡x=11+x2for every real x.\frac{d}{dx} \arctan x = \frac{1}{1 + x^2} \quad \text{for every real } x.

Remarks

Let y=arctan⁡xy = \arctan x. By the inverse function rule and tan⁡′=1+tan⁡2\tan' = 1 + \tan^2, the derivative is 11+tan⁡2y=11+x2\frac{1}{1 + \tan^2 y} = \frac{1}{1 + x^2}. So ∫01dx1+x2=arctan⁡1=π4\int_0^1 \frac{dx}{1 + x^2} = \arctan 1 = \frac{\pi}{4}. Mathlib states it as Real.hasDerivAt_arctan.

Reading path

To understand this page from the ground up, read these 75 pages in order. The foundations come first.

  1. Limit point of a set definition
  2. Local maximum definition
  3. Sequence definition
  4. Strictly monotone function definition
  5. Limit of a function definition
  6. Local minimum definition
  7. Real sequence definition
  8. Subsequence definition
  9. Continuity at a point definition
  10. Derivative definition
  11. One-sided limit definition
  12. Bounded sequence definition
  13. Cauchy sequence definition
  14. Geometric sequence definition
  15. Limit of a sequence definition
  16. Monotone sequence definition
  17. Series definition
  18. Continuous function definition
  19. Epsilon-delta definition of continuity statement
  20. Differentiable function definition
  21. Fermat's theorem on stationary points statement
  22. Limit superior definition
  23. Cauchy sequences are bounded statement
  24. Every sequence has a monotone subsequence statement
  25. Sum of a finite geometric series statement
  26. Monotone convergence theorem for sequences statement
  27. Convergent sequence definition
  28. Pointwise convergence definition
  29. Squeeze theorem statement
  30. Partial sum definition
  31. Power series definition
  32. Intermediate value theorem statement
  33. Composition of continuous functions is continuous statement
  34. Differentiable functions are continuous statement
  35. One-sided limits of a monotone function exist statement
  36. Bolzano–Weierstrass theorem statement
  37. The sequence r^n tends to zero for |r| < 1 example
  38. Radius of convergence definition
  39. Convergent series definition
  40. Uniform convergence definition
  41. Sine and cosine definition
  42. Chain rule statement
  43. Product rule statement
  44. Reciprocal rule statement
  45. Boundedness theorem statement
  46. Continuity of the inverse of a strictly monotone continuous function statement
  47. Cauchy criterion for sequences statement
  48. Absolute convergence definition
  49. Uniform convergence on a set definition
  50. Series of functions definition
  51. A series of nonnegative terms converges iff its partial sums are bounded statement
  52. Tangent function definition
  53. Sum of a series definition
  54. Extreme value theorem statement
  55. Quotient rule statement
  56. Derivative of an inverse function statement
  57. Uniformly Cauchy sequence of functions definition
  58. Arctangent definition
  59. Geometric series example
  60. Comparison test statement
  61. Rolle's theorem statement
  62. Root test statement
  63. Weierstrass M-test statement
  64. Mean value theorem statement
  65. Cauchy–Hadamard theorem statement
  66. Power series converge uniformly on smaller discs inside the radius of convergence statement
  67. A function with zero derivative is constant statement
  68. Uniform convergence of derivatives allows term-by-term differentiation statement
  69. Term-by-term differentiation statement
  70. Power series are differentiable inside the radius of convergence statement
  71. Derivative of cosine statement
  72. Derivative of sine statement
  73. Pythagorean trigonometric identity statement
  74. Derivative of tangent statement
  75. Derivative of arctangent statement

Where this leads

1 page builds on this one.

Further reading

  1. Web https://en.wikipedia.org/wiki/Differentiation_of_trigonometric_functions, Differentiating the inverse tangent function
About this page
Tag05P4B4Q22V
URIm2://05P4B4Q22V
Kindstatement, proposition
WritingW0 stub
MSC33B10, 26A24
StatusThis copy of the site has no build data. Run m2 status 05P4B4Q22V.
UsesArctangent, Derivative of an inverse function, Derivative of tangent

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