Question

cos^2 B - sin^2 B = 2 cos^2 B - 1

Answer 1

Answer:

LHS = cos²B - sin²B

= cos²B - ( 1 - cos²B)

= cos²B -1 + cos²B

= 2cos²B -1 = RHS

HENCE proved

Step-by-step explanation:

formula used,

sin²∅ = 1 - cos²∅.