Question

cos²A-sin²A+1=2 Cos²A​

Answer 1

Step-by-step explanation:

We know that

Cos2A = 2 cos^2 A -1...... (1)

Cos2A = cos^2A - sin^2 A..... (2)

Eliminating Cos2A from (1) &(2)

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

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

Hence proved

Hope it helps you buddy