Question

плиз !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer 1

1) cos B=BC/AB=12/13

Б

2) tg A=BC/AC=12/5

A

3) cos 45°=√2/2 (это табличное значение)

4) sin²+cos²=1

sin²=1-cos²

sin²=1-16/49

sin²=49-16/49

sin²=33/49

sin=√(33/49)

sin=√33/7

B

5)tg=sin/cos

cos²=1-sin²

cos²=1-9/16

cos²=16-9/16

cos ²=7/16

cos=√7/√16=√7/4

tg=3*4/√7*4

tg=3/√7

B

6)sin 45°*cos 60°*tg 30°=√2/2 *1/2 *√3/3=√6/12

Б