Question

if 2sin²B-cos²B=2,then B is​

Answer 1

Answer:

Step-by-step explanation:

2 sin²B - cos²B=2

= 2 sin²B - (1-sin²B) = 2

= 2 sin²B -1+sin²B = 2

=2 sin²B + sin²B = 2+1

= 2 sin²B + sin²B = 3

take sin²B as common

= sin²B ( 2+1) = 3

= 3 sin²B = 3      ⇒ sin²B = 1

⇒ sin B = √1   ⇒ sinB = sin 90°

∴ B = 90°