Show $\tan(x)+\tan(y)+\tan(z) = \tan(x) \tan(y) \tan(z)$
32197
Prove that $\tan A + \tan B + \tan C = \tan A\tan B\tan C,$ $A+B+C = 180^\circ$
81720
$f(x) + f(x+f(y)) = y + f(f(x) + f(f(y)))$
155341
Proving or disproving inequality $ \frac{xy}{z} + \frac{yz}{x} + \frac{zx}{y} \ge x + y + z $
96388
Prove $\sin(x)\tan(x) > x^2$ for $x \in ( \,0, \frac{\pi}{2}) \,$
41383
Prove that $(x+y+z)^2(yz+zx+xy)^2 \leq 3(y^2+yz+z^2)(z^2+zx+x^2)(x^2+xy+y^2)$
31379
Relationship between $\tanh x$ and $\arctan x$
82286
Derivation of asymptotic solution of $\tan(x) = x$.
142673
Evaluate $\tan^{2}(20^{\circ}) + \tan^{2}(40^{\circ}) + \tan^{2}(80^{\circ})$
31448
Calculate $\int\left( \sqrt{\tan x}+\sqrt{\cot x}\right)dx$
82758
To prove $ \tan(A) + 2 \tan(2A) +4\tan4A + 8 \cot8A =\cot(A) $
147113
How to solve $2 \tan x / (1 - (\tan x)^2) = (\sin 2x)^2$?
125817
show this inequality $(x+y)^3+(y+z)^3+(z+w)^3+(w+x)^3\ge 8(x^2y+y^2z+z^2w+w^2x)$
108704
Help with proof of $|x+y| \geq |x|-|y|$
82961
Show that $\left| \frac{1}{x}-\frac{1}{z} \right| \le \left|\frac{1}{x} - \frac{1}{y} \right| + \left|\frac{1}{y} - \frac{1}{z} \right|$.
82170
Solve $x = \frac{1}{2}\tan(x)$
77978
Show that $\frac {\sin x} {\cos 3x} + \frac {\sin 3x} {\cos 9x} + \frac {\sin 9x} {\cos 27x} = \frac 12 (\tan 27x - \tan x)$
146594
Prove that $\frac{d}{dx}(\tan^{-1}(x))=\frac{1}{1+x^2}dx$