$\tan^2 10^\circ+\tan^2 50^\circ+\tan^2 70^\circ=9$
33100
Trigonomnetric equality involving tg
51842
Simplify $\prod_{k=1}^5\tan\frac{k\pi}{11}$ and $\sum_{k=1}^5\tan^2\frac{k\pi}{11}$
9539
$\alpha$ and $\beta$ are solution of $a \cdot \tan\theta + b \cdot \sec\theta = c$ show $ \tan(\alpha + \beta) = \frac{2ac}{a^2 - c^2}$
60559
How prove this $x^3<\sin^2{x}\tan{x},x\in\left(0,\dfrac{\pi}{2}\right)$
17769
Show that $\frac{\sin x}{\cos 3x}+\frac{\sin 3x}{\cos 9x}+\frac{\sin 9x}{\cos 27x} = \frac{1}{2}\left(\tan 27x-\tan x\right)$
82085
Without solving the equation, show that all nine roots of $(𝑧 − 1)^{10} = 𝑧^{10}$ lie on the line $Re (𝑧) = \frac{1}{2}$
82170
Solve $x = \frac{1}{2}\tan(x)$
32183
A "fast" way for  computing $ \prod \limits_{i=1}^{45}(1+\tan i^\circ) $?
110955
Find the coefficient of $x^9$ in $(1+x)(1+x^2)(1+x^3)\cdots(1+x^{100})$
143070
If $\sin A + \cos A + \tan A + \cot A + \sec A + \csc A = 7$ then $x^2 - 44x - 36 = 0$ holds for $x=\sin 2A$
81337
How to solve $(1-\tan^2x)\sec^2x+2^{\tan^2x}=0$
124248
$1+\frac {1}{4}(1+\frac {1}{4}) +\frac {1}{9}(1+\frac {1}{4} +\frac {1}{9})+....$
62446
Solve the equation $x^2+\frac{9x^2}{(x+3)^2}=27$
48956
Simplify $\arctan (\frac{1}{2}\tan (2A)) + \arctan (\cot (A)) + \arctan (\cot ^{3}(A)) $
156786
Show that $15\mid 21n^5 + 10n^3 + 14n$ for all integers $n$.
81750
$4 \sin 72^\circ \sin 36^\circ = \sqrt 5$
109640
How do i find $(1+i)^{100}?$