**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

P^{2} + B^{2} =H^{2}

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 = cos^{2} A - sin^{2}A= 7/25

So LHS=RHS,so the statement is true