Question

giải chi tiết hộ em với ạ

Answer 1

Bài 1:

a. $\sin ^2a+\cos ^2a=1$

$\cos ^2a=1-\sin ^2a=1-(\frac{1}{3})^2=\frac{8}{9}$

$\Rightarrow \cos a=\frac{2\sqrt{2}}{3}$ (do $\cos a>0$)

b.

\(\sin 32-\cos 58+2\frac{\tan 33}{\cot 57}-3(\sin ^210+\sin ^280)\)

\(=\cos (90-32)-\cos 58+2\frac{\tan 33}{\tan (90-57)}-3(\sin ^210+\cos ^2(90-80))\)

\(=\cos 58-\cos 58+2\frac{\tan 33}{\tan 33}-3(\sin ^210+\cos ^210)\)

\(=0+2.1-3.1=-1\)