Proof of Angles going beyond 90 deg in Trigonometry
135543
Proof of Angles going beyond 90 degrees in Trigonometry
109171
How to evaluate this trigonometric limit?
99012
Finding an angle in a $80^\circ$-$80^\circ$-$20^\circ$ triangle (variant involving $70^\circ$ and $60^\circ$)
21745
Proof of Heron's Formula for the area of a triangle
18005
Angle notation for complex numbers in polar form
9479
$\sum \cos$ when angles are in arithmetic progression
40869
Solving Trigonometric Limits
96328
Proving $e^{i\pi} = -1$ without proving $e^{ix} = \cos x + i\sin x$
85872
Prove $1 + \tan^2\theta = \sec^2\theta$
71325
Trigonometry pre calculus level question
58932
Hard contest type trigonometry proof
50277
Relationship between cosines of angles in 4 dimensions
5947
Limit of a trigonometric rational expression
24656
Proving that $\frac{\csc\theta}{\cot\theta}-\frac{\cot\theta}{\csc\theta}=\tan\theta\sin\theta$
88283
Proving the length of angle bisector
27513
Trigonometric bounds
12646
In acute angle triangle, prove that $\cos (A-B) \cos (B-C) \cos (C-A)\ge 8\cos A \cos B \cos C$