document.write( "Question 1160863: find the coefficient of x^4 in the expansion of (x+1/x)^(5) x (x-1/x)^(3) \n" ); document.write( "
Algebra.Com's Answer #784276 by Edwin McCravy(20056)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "\"%28x%2B1%2Fx%29%5E%285%29%2A%28x-1%2Fx%29%5E%283%29\"\r\n" );
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document.write( "\"%28%28x%5E2%2B1%29%2Fx%5E%22%22%29%5E5%28%28x%5E2-1%29%2Fx%5E%22%22%29%5E3\"\r\n" );
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document.write( "\"expr%28%28x%5E2%2B1%29%5E5%2Fx%5E5%29%2Aexpr%28%28x%5E2-1%29%5E3%2Fx%5E3%29\"\r\n" );
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document.write( "\"%28%28x%5E2%2B1%29%5E5%28x%5E2-1%29%5E3%29%2Fx%5E8\"\r\n" );
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document.write( "Using Pascal's triangle:\r\n" );
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document.write( "So we only need to multiply the terms which will give us\r\n" );
document.write( "a term in x12 on top since we have x8 on the bottom, and\r\n" );
document.write( "the exponents will subtract to give exponent 4.\r\n" );
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document.write( "\"%28x%5E10%29%283x%5E2%29%2B%285x%5E8%29%28-3x%5E4%29%2B%2810x%5E6%29%28x%5E6%29\"\r\n" );
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document.write( "\"3x%5E12-15x%5E12%2B10x%5E12\"\r\n" );
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document.write( "\"-2x%5E12\"\r\n" );
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document.write( "So the coefficient of x4 in the original problem is also -2\r\n" );
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document.write( "Edwin
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