Verify sin4x - sin2x = cos4x-cos2x

sin⁴x - sin²x = cos⁴x - cos²x

Solve the right hand side of the equation

That's

sin⁴x - sin²x

From trigonometric identities

So we have

sin⁴x - ( 1 - cos²x)

sin⁴x - 1 + cos²x

sin⁴x = ( sin²x)(sin²x)

That is

( sin²x)(sin²x)

So we have

( 1 - cos²x)(1 - cos²x) - 1 + cos²x

Expand

1 - cos²x - cos²x + cos⁴x - 1 + cos²x

1 - 2cos²x + cos⁴x - 1 + cos²x

Group like terms

That's

cos⁴x - 2cos²x + cos²x + 1 - 1

Simplify

We have the final answer as

So we have

Since the right hand side is equal to the left hand side the identity is true

Hope this helps you

yes. we do proportions in probabilities.