Question

cos2 theta /1+2sin2 theta
= Tan pi/4 - theta​

pls Help me pls pls pls

Answer 1

Answer:

question is wrong. It should be cos 2theta/(1+sin2theta)

RHS = tan (45 - theta) = (tan 45 - tan theta)/(1 + tan45 . tan theta)

= (1 - tan theta)/(1 + tan theta) since tan 45 = 1

= (1 - sin/cos)/(1 + sin/cos)

=(cos-sin)/(cos + sin)

=(cos - sin)×(cos + sin)/((cos+sin)×(cos + sin))

=(cos^2 - sin^2)/(cos + sin)^2

=cos 2 theta/(cos^2 + sin^2 + 2.sin.cos)

=cos 2 theta/(1 + sin 2 theta)

= LHS

please don't give wrong question