Tuesday, 9 April 2013

trigonometry - Prove or disprove $frac{sqrt{1+tan x}}{cot x} = frac{1+sin x}{cos x}$



I have tried to prove the identity \begin{equation}
\frac{\sqrt{1+\tan x}}{\cot x} = \frac{1+\sin x}{\cos x}
\end{equation}

by $t$-substitution but seem not to work. Please don't solve(don`t post the answer on this site) this question for me just try it and give me hints on how I should go about it. Or if you like you can post but I wanted to try using some hints that you would give first.


Answer



If $x=\pi/4$ we have: $$\frac{\sqrt{1+1}}{1}=\sqrt{2}$$ on the left, but $$\frac{1+ \frac{1}{\sqrt{2}}}{1/\sqrt{2}}=\sqrt{2}+1$$ on the right.



These are not equivalent.


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