I would like to prove that sinX^4 - cosX^4 + 2cosX^2 equals to 1 using sin^2 theta+ cos^2 theta=1 and a^2-b^2=(a-b)(a+b). I am completely stuck though, and do not know where to begin. Any advice would be appreciated.
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Hello Note that . Can you factor this using ? Hint (highlight to read) : * let a=(sin x)^2 and b=(cos x)^2 *
Originally Posted by Pandora I would like to prove that sinX^4 - cosX^4 + 2cosX^2 equals to 1 using sin^2 theta+ cos^2 theta=1 and a^2-b^2=(a-b)(a+b). I am completely stuck though, and do not know where to begin. Any advice would be appreciated. Let's focus on this term first: using the formula , we see that Now, we see that the equation now becomes Simplifying, we get Does this make sense? --Chris
Thank you both. It seems pretty clear now =) This forum is so efficient, and I will be definetly using it in the future.
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