Question

if tanA=n tanB and sinA=msinB,prove that cos square A=m square-1 /n square-1

Answer 1

Here is the answer to your question. ⇒m 2 n 2 cos2A = sin2A ⇒m 2 n 2 cos2A = 1 cos2A ⇒n 2cos2A cos2A = m 2 1 ⇒ (n 2 1) cos2A = m 2 1