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## Homework Statement

Prove the Identity: tan²θ - sin²θ = tan²θsin²θ

## Homework Equations

## The Attempt at a Solution

Well I got up to (sin²θ/cos²θ) - (sin²θcos²θ/cos²θ) = sin⁴θ/cos²θ

I got the answer cause my calculator says sin²θ - sin²θcos²θ = sin⁴θ

But I don't know how sin²θ - sin²θcos²θ = sin⁴θ.

How do you subtract sin²θcos²θ with sin²θ?

Also while I'm at it, how does sin⁴θ - cos⁴θ = 1 - 2cos²θ?

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