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tolli
How to verify the following identitie:cot(-t)+tan(-t)/cot(t)=-sec^2t
\[\frac{ -\cot(t)-tant }{ \cot(t) }=\frac{- \frac{ cost }{ sint }-\frac{ sint }{cost } }{ \frac{ cost }{sint } }=-\frac{ \frac{ \cos ^{2}t+\sin ^{2}t }{sintcost } }{ \frac{ cost }{ sint }}\] \[-\frac{ 1 }{sint cost }.\frac{ sint }{ cost }=-\frac{ 1 }{\cos ^{2}t }=-\sec ^{2}t\]