Question

If 3 cot A = 4, check whether (1-tan^2 A)/(1+tan^2 A) = cos^2 A - sin^2 A or not

Answer 1

Solution:  Given
Cot A=4/3 Or B/P=4/3
Let B=4k and P=3k
So in a right angle triangle with angle A
P² + B² =H²
H=5k
Now tan A=1/cot A=3/4
Cos A=B/H=4/5
Sin A=P/H=3/5
Let us take the LHS

RHS = cos² A -  sin²A= 7/25
So LHS=RHS,so the statement is true