Identitas trigonometri Tan x sin x + cos x = sec x

tan x sin x + cos x
= sin² x /cos x + cos² x /cos x
= 1/cos x
= sec x
q.e.d

Trigonometry Identity.

[tex]\displaystyle \tan x \sin x+\cos x\\ =\frac{\sin x}{\cos x}\sin x+\frac{\cos^2 x}{\cos x}\\ =\frac{\sin^2 x+\cos^2 x}{\cos x}\\ =\frac{1}{\cos x}=\sec x[/tex]
Proved.