if-x-0-pi-2-then-prove-that-2-1-cotx-tan-3-x-cot-3-x-1-tanx-1-cotx-3-2-

Question Number 155776 by mathdanisur last updated on 04/Oct/21

if x \in (0; \frac{π}{2}) then prove that :

\frac{2 + (1 + \cot x) (\tan^{3} x + \cot^{3} x)}{(1 + \tan x) (1 + \cot x)} ⩾ \frac{3}{2}