Interesting Trigonometry Identity
116223
Show that the angles satisfy $x+y=z$
103487
Integration of the cardinal sine
24656
Proving that $\frac{\csc\theta}{\cot\theta}-\frac{\cot\theta}{\csc\theta}=\tan\theta\sin\theta$
111102
Prove the Trigonometric Identity: $\frac{\sin x}{1-\cos x} = \frac{1+\cos x}{\sin x}$
17580
Combinatorics That Looks Similar to Vandermonde's Identity
108688
An identity involving products of sums
135543
Proof of Angles going beyond 90 degrees in Trigonometry
84420
When is $\sin(x) = \cos(x)$?
82027
How to derive compositions of trigonometric and inverse trigonometric functions?
34386
Sum of a complex, finite geometric series and its identity
139625
Proof of a Fibonacci identity
89003
Finding a trigonometric polynomial
72157
Elementary proof of tangent half angle formula
147410
ArcTan(2) a rational multiple of $\pi$?
140851
Precalculus unit circle with imaginary axis.
93212
Express $\sqrt{3}\sin\theta - \cos\theta$ as: $a\cos (\theta + \alpha) $
33100
Trigonomnetric equality involving tg