no 39 caranya gimana bingung..?

tanx sinx + cosx = ..

Identitas trigonometri :
sin^2x + cos^2x = 1
sec x = 1/cos x
tan x = sin x / cos x

tanx sinx + cosx
= (sin x/cos x) sin x + cosx

Samakan penyebut

sin^2x/cos x + cos^2x /cos x
= 1/cosx
= sec x

Semoga membantu