Buktikan identitas berikut tan kuadrat x +1+tan x. Sec x=1+sin x per cos kuadrat x

Trigonometri.

[tex]\displaystyle \tan^2 x+1+\tan x \sec x\\ =\left ( \frac{\sin x}{\cos x} \right )^2+1+\frac{\sin x}{\cos x}~\frac{1}{\cos x}\\ =\frac{\sin^2 x+\cos^2 x}{\cos^2 x}+\frac{\sin x}{\cos^2 x}\\ =\frac{1+\sin x}{\cos^2 x}[/tex]
Terbukti.