Question

P.T. sin⁴ + cos⁴ = 1 - 2 sin² cos²​

Answer 1

Answer:

Step-by-step explanation:

LHS= sin^4+cos^4

=(sin^2)^2+(cos^2)^2

use a^2+b^2=(a+b)^2-2ab

=(sin^2+cos^2)^2 - 2sin^2+cos^2

=1 - 2sin^2cos^2