unlmath
Dec 6, 2011, 07:40 PM
(csc(x) cot(x))(1-cos(x))=sin(x)
Aurora2000
Dec 7, 2011, 02:42 AM
Use \sin x=\cos x\tan x and \sin^2 x+\cos^2 x=1 :
(\frac{1}{\sin x} +\frac{1}{\tan x})(1-\cos x) =
\frac{1}{\sin x} +\frac{1}{\tan x} - \frac{\cos x}{\sin x} -\frac{\cos x}{\tan x}=
\frac{1}{\sin x}-\frac{\cos x}{\tan x}\frac{\cos x}{\cos x} =
\frac{1-\cos^2 x}{\sin x}=\sin x