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Old November 5th, 2009, 02:51 PM
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Default Help in simplifying equasion

Hi All,
I'm new to this blessed site.
Would appreciate someone's help in simplifying the following equation:



Many thanks !

Last edited by naorca; November 6th, 2009 at 03:36 AM.
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Old November 5th, 2009, 02:57 PM
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sec^2(x) = 1+tan^2(x),

Can ya finish?
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Old November 5th, 2009, 03:12 PM
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Old November 5th, 2009, 03:31 PM
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\frac{\tan(x) \sin(x)}{\sec^2(x) - 1} = \frac{\tan(x) \sin(x)}{1 + \tan^2(x) - 1} = \frac{\tan(x) \sin(x)}{\tan^2(x)} = \frac{\sin(x)}{\tan(x)}.

And \tan(x) = \frac{\sin(x)}{\cos(x)} so we have...

\frac{\sin(x)}{\tan(x)} = \frac{\sin(x)}{\frac{\sin(x)}{\cos(x)}} = \cos(x).
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Old November 5th, 2009, 03:37 PM
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If you need clarification on the last step then...

\frac{\cos(x)}{\cos(x)} = 1 so...

\frac{\sin(x)}{\frac{\sin(x)}{\cos(x)}} \cdot 1 = \frac{\sin(x)}{\frac{\sin(x)}{\cos(x)}} \cdot \frac{\cos(x)}{\cos(x)} = \frac{\sin(x)\cos(x)}{\frac{\sin(x)\cos(x)}{\cos(x)}} = \frac{\sin(x) \cos(x)}{\sin(x)} = \cos(x)
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Old November 5th, 2009, 04:02 PM
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Thanks !
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