Question

Cos2A=7/8, sinA=7/7 proved

Answer 1

Answer:

Step-by-step explanation:

cos2A = 1-2sin²A

7/8=1-2sin²A

2sin²A=1-7/8

2sin²A=1/8

sin²A=1/16

sinA=1/4,-1/4

ur question is not clear but i assumed u wanted sinA value

hope it helps...