buktikan identitas trigonometri no 2 dan 19

Gatau bener atau salah. Kalo salah maafin yaa

2) sec x . sin x = 1/(cos x) . sin x = (sin x)/(cos x) = Tan x

9) cosec^2 x - (cos^2 x)/(sin^2 x)
= 1/(sin^2 x) - (cos^2 x)/(sin^2 x)
= (1 - cos^2 x)/(sin^2 x)
= (sin^2 x)/(sin^2 x)
= 1

^ = pangkat

19) (sin^2 x)/(cos^4 x + cos^2 x sin^2 x)
= (sin^2 x)/(cos^2 x (cos^2 x + sin^2 x))
= (sin^2 x)/(cos^2 x (1))
= (sin^2 x)/(cos^2 x)
= tan^2 x