Question

if 3 cot A = 4 find 1-tan2a/1+tan2a= cos2a-sin2a or not​

Answer 1

Answer:

no 1-tan2a/1+tan2a=cos 2a-sin 2a is not equal

Step-by-step explanation:

Cot A=4/3

tan A =3/4, CosA=4/5 ,SinA=3/5

tan (2A) = 2tana/1-tan^2a = 2×3/4/1-(3/4)^2

tan 2A= 24/7

Cos 2A= Cos^2 A-Sin^2 A=(4/5)^2-(3/5)^2

=16/25-9/25

= 7/25

Sin2A=2Sin A Cos A=2×3/5×4/5=24/25

substitute all the values at LHS and RHS

1-24/7/1+24/7=7/25-24/25

-17/31= -17/25

therefore it is not equal