Question

prove that sin^4Φ+cos^4Φ=1-2sin^2Φcos^2Φ​

Answer 1

Answer:

Step-by-step explanation:

sin^4Φ+cos^4Φ

(sin^2 phi)^2+(cos^2 phi)^2

we know a^2+b^2

(a+b)^2-2ab

therefore

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

1-2sin^2Φcos^2Φ​