Question

Prove that cos square A minus sin square A equal to 1 minus 2 sin square A

Answer 1

Answer:

Step-by-step explanation:

sin^2+cos^2A= 1

cos^2A=1-sin^2A.......................1.

cos^2A - sin^2A = 1-2sin^2A......................2.

Putting eq. 1. in 2.

L.H.S    =1-sin^2A - sin^2A

            =1-2sin^2A

HENCE PROVED!!!!!!!!!!!!

Answer 2

Given: The equation.

To Prove: $cos^{2} A-sin^{2} A=1-2sin^{2}A$

Solution:

As we know the identity

$cos^{2} A+sin^{2} A=1$

$cos^{2} A=1-sin^{2} A$   (Equation 1)

$cos^{2} A-sin^{2}A$   (Equation 2)

Put eq 1 in eq 2.

= $1-sin^{2}A-sin^{2}A$

= $1-sin^{2} A$

$cos^{2} A-sin^{2} A=1-2sin^{2}A$

Hence, proved.