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## Main Question or Discussion Point

Anyone know if the difference of cos^2 and sin^2 is some obscure identity that no one's heard of?

Edit: nevermind. Shaum's tells me that cos^2 - sin^2 = cos(2a). GO SHAUMS!!

Edit: nevermind. Shaum's tells me that cos^2 - sin^2 = cos(2a). GO SHAUMS!!

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