# Identity

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• April 27th 2009, 04:21 PM
jumpman23
Identity
find an expression that completes the identity,

cos^2x/1-sinx = ?
• April 27th 2009, 05:07 PM
skeeter
Quote:

Originally Posted by jumpman23
find an expression that completes the identity,

cos^2x/1-sinx = ?

hint ... $\cos^2{x} = 1 - \sin^2{x}$ ... then factor
• April 27th 2009, 05:27 PM
jumpman23
I'm still confused about what to do. How do you use this pythagorean identity with this?
• April 27th 2009, 05:30 PM
skeeter
Quote:

Originally Posted by jumpman23
I'm still confused about what to do. How do you use this pythagorean identity with this?

factor $1-\sin^2{x}$ and see.
• April 27th 2009, 05:33 PM
jumpman23
does it end up equaling 1?
• April 27th 2009, 05:42 PM
skeeter
$\frac{\cos^2{x}}{1 - \sin{x}} = \frac{1 - \sin^2{x}}{1 - \sin{x}} = \frac{(1 - \sin{x})(1 + \sin{x})}{1 - \sin{x}} = 1 + \sin{x}
$