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renagirl99
Jul 12, 2010, 09:46 AM
Can someone help me verify this trig identity?
(sin(x))/(1-cos(x))-(sin(x)cos(x))/(1+cos(x))=csc(x)(1+cos^2(x))

galactus
Jul 12, 2010, 10:28 AM
O I appluad you on your use of grouping symbols. Few do that when they post a problem.

\frac{sin(x)}{1-cos(x)}-\frac{sin(x)cos(x)}{1+cos(x)}

Cross multiply and simplify:

\frac{sin(x)+sin(x)cos^{2}(x)}{1-cos^{2}(x)}

\frac{sin(x)(1+cos^{2}(x))}{sin^{2}(x)}

\frac{1+cos^{2}(x)}{sin(x)}

csc(x)(1+cos^{2}(x))

renagirl99
Jul 12, 2010, 11:03 AM
how did you get (1+cos^2(x)) in the third step?

galactus
Jul 13, 2010, 06:19 AM
Factor out the sin(x) in the numerator.