Sunday, 3 August 2014

trigonometry - How can we know what cos(-75) is?

We need to prove it using the sum and difference formula. We also need to use special triangles. how? I've tried doing cos(a-b) but I did cos(-30)cos(-75)

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real analysis - How to find limhrightarrow0fracsin(ha)h

How to find lim without lhopital rule? I know when I use lhopital I easy get $$ \lim_{h\rightarrow 0}...