Power-reduction formula for cosine

Reading path

To understand this page from the ground up, read these 61 pages in order. The foundations come first.

1. Limit point of a set definition
2. Local maximum definition
3. Sequence definition
4. Limit of a function definition
5. Local minimum definition
6. Real sequence definition
7. Subsequence definition
8. Continuity at a point definition
9. Derivative definition
10. Bounded sequence definition
11. Cauchy sequence definition
12. Geometric sequence definition
13. Limit of a sequence definition
14. Monotone sequence definition
15. Series definition
16. Continuous function definition
17. Fermat's theorem on stationary points statement
18. Limit superior definition
19. Cauchy sequences are bounded statement
20. Sum of a finite geometric series statement
21. Monotone convergence theorem for sequences statement
22. Every sequence has a monotone subsequence statement
23. Convergent sequence definition
24. Pointwise convergence definition
25. Squeeze theorem statement
26. Cauchy product definition
27. Partial sum definition
28. Power series definition
29. Bolzano–Weierstrass theorem statement
30. The sequence r^n tends to zero for |r| < 1 example
31. Radius of convergence definition
32. Uniform convergence definition
33. Convergent series definition
34. Sine and cosine definition
35. Boundedness theorem statement
36. Uniform convergence on a set definition
37. Cauchy criterion for sequences statement
38. Absolute convergence definition
39. Series of functions definition
40. A series of nonnegative terms converges iff its partial sums are bounded statement
41. Sum of a series definition
42. Extreme value theorem statement
43. Uniformly Cauchy sequence of functions definition
44. Geometric series example
45. Comparison test statement
46. Cauchy product of absolutely convergent series statement
47. Rolle's theorem statement
48. Root test statement
49. Weierstrass M-test statement
50. Angle addition formulas statement
51. Mean value theorem statement
52. Cauchy–Hadamard theorem statement
53. Power series converge uniformly on smaller discs inside the radius of convergence statement
54. A function with zero derivative is constant statement
55. Uniform convergence of derivatives allows term-by-term differentiation statement
56. Term-by-term differentiation statement
57. Power series are differentiable inside the radius of convergence statement
58. Derivative of cosine statement
59. Derivative of sine statement
60. Pythagorean trigonometric identity statement
61. Power-reduction formula for cosine statement