Question

Show $\frac{\cos(n\theta)-\cos(n+1)\theta)}{2-2\cos\theta}=\frac{\sin(n+1/2)\theta}{2\sin(\theta/2)}$

score 85 · Answer 1 · 2018-02-04 17:32:25

85

Views

Show $\frac{\cos(n\theta)-\cos(n+1)\theta)}{2-2\cos\theta}=\frac{\sin(n+1/2)\theta}{2\sin(\theta/2)}$

Published on 04 Feb 2018 - 17:32

score 93 · Answer 2 · 2026-03-26 23:52:28

93

Views

Relation between altitudes and three angles and their sides.

Published on 26 Mar 2026 - 23:52

score 131 · Answer 3 · 2026-03-26 07:57:46

131

Views

Initial guess for babylonian method when calculating hypothenuse

Published on 26 Mar 2026 - 7:57

score 306 · Answer 4 · 2026-03-30 02:01:56

306

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score 104 · Answer 5 · 2018-02-05 02:51:29

104

Views

Proving $\frac{\cos a - \sin a + 1}{\cos a + \sin a - 1 } = \frac{\sin a}{1-\cos a}$

Published on 05 Feb 2018 - 2:51

score 55 · Answer 6 · 2018-02-05 08:09:12

55

Views

Solving a trigonometry equation

Published on 05 Feb 2018 - 8:09

score 62 · Answer 7 · 2018-02-05 08:26:29

62

Views

Find first positive integer $n$ (where $n$ not equals to $0$) for which $\cos n\theta = 1$?

Published on 05 Feb 2018 - 8:26

score 123 · Answer 8 · 2026-03-25 09:18:52

123

Views

How to find the minimum and maximum value of value of $(\sin^{-1}(x))^4+(\cos^{-1}(x))^4$?

Published on 25 Mar 2026 - 9:18

score 53 · Answer 9 · 2026-03-25 16:06:54

53

Views

HitTest - Calculate offset created by perspective.

Published on 25 Mar 2026 - 16:06

score 55 · Answer 10 · 2026-03-20 10:46:20

55

Views

I want to find the $\cos ({\hat{BCD}})$. However, I don't have any idea about how to. Can you assist?

Published on 20 Mar 2026 - 10:46

score 64 · Answer 11 · 2018-02-06 03:11:25

64

Views

Why is the domain of this implicit function all $x\in R$?

Published on 06 Feb 2018 - 3:11

score 252 · Answer 12 · 2018-02-06 06:47:46

252

Views

Find limit of $\lim_{x\to 0}\frac{\sin^{200}(x)}{x^{199}\sin(4x)}$, if it exists

Published on 06 Feb 2018 - 6:47

score 108 · Answer 13 · 2026-03-19 22:36:19

108

Views

$\cos(\frac{2 \pi}{n}) = 1 \ \forall n \geq 1$? Need help in finding my mistake.

Published on 19 Mar 2026 - 22:36

score 92 · Answer 14 · 2026-03-27 15:23:37

92

Views

Is it possible ti find $∠X$ in below figure?

Published on 27 Mar 2026 - 15:23

score 375 · Answer 15 · 2026-03-20 09:49:37

375

Views

find the missing angles in this quadrilateral

Published on 20 Mar 2026 - 9:49

List Question

Show $\frac{\cos(n\theta)-\cos(n+1)\theta)}{2-2\cos\theta}=\frac{\sin(n+1/2)\theta}{2\sin(\theta/2)}$

Relation between altitudes and three angles and their sides.

Initial guess for babylonian method when calculating hypothenuse

Find Position in Broken Clock

Proving $\frac{\cos a - \sin a + 1}{\cos a + \sin a - 1 } = \frac{\sin a}{1-\cos a}$

Solving a trigonometry equation

Find first positive integer $n$ (where $n$ not equals to $0$) for which $\cos n\theta = 1$?

How to find the minimum and maximum value of value of $(\sin^{-1}(x))^4+(\cos^{-1}(x))^4$?

HitTest - Calculate offset created by perspective.

I want to find the $\cos ({\hat{BCD}})$. However, I don't have any idea about how to. Can you assist?

Why is the domain of this implicit function all $x\in R$?

Find limit of $\lim_{x\to 0}\frac{\sin^{200}(x)}{x^{199}\sin(4x)}$, if it exists

$\cos(\frac{2 \pi}{n}) = 1 \ \forall n \geq 1$? Need help in finding my mistake.

Is it possible ti find $∠X$ in below figure?

find the missing angles in this quadrilateral

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