Question

Q.4 cos^4 theta + sin^4 theta​

Answer 1

Answer:

Cos⁴ theta + sin⁴ theta

(Cos²)² theta + (sin²)² theta

Using formula :- a² + b² = (a+b)² - 2ab

(Cos²)² theta + (sin²)² theta

= (cos² + sin²)² - 2sin²thetacos²theta

= 1² - 2sin²cos² ( since, sin² + cos² =1)

= 1 - 2 sin² theta cos² theta Ans.....