Sunday, February 24, 2019

trigonometry - Simplify $frac{cos x+cos y}{sin(x+y)}$

I have tried all kinds of different method, and have spent more than an hour on this problem, also looked upon internet looking for similar problems but none worked. All I got in the end, I can get my answers to $\dfrac{\csc y+\csc x}{\tan x+\tan y}$, but pretty sure that doesn't answer the problem, and tried using identities but in the end they always become much more complicated than I couldn't clear up, so I pretty much did the opposite of simplify.



thank u for your comment
how to u use the sum to product rule on sin(x+y) i only found identity that sin(x+y)= sinxcosy+cosxsiny?
does sin(x+y)= sinx+siny? or u used the sum rule and then the product rule of sinx*cosy identity which didn't work for me

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