Question

cos^4 A -sin^4A=1-sin^2 A​

Answer 1

Answer:

question is wrong in right side

1-2sin2A

Step-by-step explanation:

cos4A=(cos2A) 2

sin4A=(sin2A)2

(cos2A) 2-(sin2A)2 ... a2-b2=(a+b) (a-b)

(cos2A+sin2A)(cos2A-sin2A) ... cos2A+sin2A=1

1(1-sin2A-sin2A) ....cos2A=1-sin2A

1(1-2sin2A)

1-2sin2A