LS =
cos^2 B - sin^2 B
= cos^2 B - (1 - cos^2 B)
= 2cos^2 B - 1
= RS
1) Verify the identity
cos^2 B - sin^2 B = 2 cos^2 B -1
I know that cos^2 B - sin^2 B = 2 cos^2 B -1 by the double angle formula but I do not know how to show this.
1 answer