document.write( "Question 639049: if f(x) = $\"%281%2Bx%29%2F%281-x%29\"$ show that f(f(tan(q))) = -cot(q) ( this question is taken from 11th standard maths text chapter trigonometry / functions , q refers to angle) \n" ); document.write( "

Algebra.Com's Answer #402569 by Edwin McCravy(20065) $\"\"$ $\"About$

You can put this solution on YOUR website!

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document.write( "f(x) = \r\n" );
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document.write( "The trick is to get f(f(x)) and simplify it BEFORE \r\n" );
document.write( "you substitute tan(q)\r\n" );
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document.write( "f(f(x)) = \r\n" );
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document.write( "Multiply top and bottom by LCD of (1-x)\r\n" );
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document.write( "f(f(x)) = \r\n" );
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document.write( "f(f(x)) = \r\n" );
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document.write( "f(f(x)) = \r\n" );
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document.write( "f(f(x)) = \r\n" );
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document.write( "f(f(x)) = \r\n" );
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document.write( "Now substitute x = tan(q)\r\n" );
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document.write( "f(f(tan(q))) = \r\n" );
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document.write( "f(f(tan(q))) = -cot(q)\r\n" );
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document.write( "Edwin

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