Prove that :$\tan 70 - \tan 20 = 2\tan 40 + 4\tan 10$
108916
On the proof $\tan 70°-\tan 20° -2 \tan 40°=4\tan 10°$
145632
Proving $\frac{1}{\cos^2\alpha}<\frac{\tan\beta-\tan\alpha}{\beta-\alpha}<\frac{1}{\cos^2\beta}$
88989
Why $x<\tan{x}$ while $0<x<\frac{\pi}{2}$?
123920
How prove this inequality $\tan{(\sin{x})}>\sin{(\tan{x})}$
74143
Simplifying and evaluating $\cot 70^\circ+4\cos 70^\circ$
60559
How prove this $x^3<\sin^2{x}\tan{x},x\in\left(0,\dfrac{\pi}{2}\right)$
81337
How to solve $(1-\tan^2x)\sec^2x+2^{\tan^2x}=0$
48956
Simplify $\arctan (\frac{1}{2}\tan (2A)) + \arctan (\cot (A)) + \arctan (\cot ^{3}(A)) $
24656
Proving that $\frac{\csc\theta}{\cot\theta}-\frac{\cot\theta}{\csc\theta}=\tan\theta\sin\theta$
32197
Prove that $\tan A + \tan B + \tan C = \tan A\tan B\tan C,$ $A+B+C = 180^\circ$
115733
Proving that $\sec\frac{\pi}{11}\sec\frac{2\pi}{11}\sec\frac{3\pi}{11}\sec\frac{4\pi}{11}\sec\frac{5\pi}{11}=32$
97011
Proving that $\prod_{k=1}^{n}\tan\left(\frac{\pi k}{2n+1}\right)=\sqrt{2n+1}$ using geometry
154172
Finding $\tan t$ if $t=\sum\tan^{-1}(1/2t^2)$
13297
Prove the following trigonometric identity without a calculator involved
7296
Prove $(1-\cos x)/\sin x = \tan x/2$
99012
Finding an angle in a $80^\circ$-$80^\circ$-$20^\circ$ triangle (variant involving $70^\circ$ and $60^\circ$)
59922
If $A = \tan6^{\circ} \tan42^{\circ},~~B = \cot 66^{\circ} \cot78^{\circ}$ find the relation between $A$ and $B$