document.write( "Question 966196: Please proof that:
\n" ); document.write( "sin^4x+cos^4x = 1-2sin^2xcos^2x \n" ); document.write( "
Algebra.Com's Answer #590798 by Edwin McCravy(20056)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "\"sin%5E4%28x%29%2Bcos%5E4%28x%29\"\"%22%22=%22%22\"\"1-2sin%5E2%28x%29cos%5E2%28x%29\"\r\n" );
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document.write( "(((sin^2(x)sin^2(x)+cos^2(x)cos^2(x)}}}\r\n" );
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document.write( "Substitute 1-cosē(x) for the second sinē(x) and\r\n" );
document.write( "Substitute 1-sinē(x) for the first cosē(x)\r\n" );
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document.write( "(((sin^2(x)(1-cos^2(x))+(1-sin^2(x))cos^2(x)}}}\r\n" );
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document.write( "Distribute\r\n" );
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document.write( "\"sin%5E2%28x%29-sin%5E2%28x%29%2Bcos%5E2%28x%29-sin%5E2%28x%29cos%5E2%28x%29\"\r\n" );
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document.write( "Rearrange and group terms:\r\n" );
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document.write( "\"%28sin%5E2%28x%29%5E%22%22%2Bcos%5E2%28x%29%29-sin%5E2%28x%29-sin%5E2%28x%29\"\r\n" );
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document.write( "Substitute 1 for sinē(x)+cosē(x) and combine last two like terms.\r\n" );
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document.write( "\"1-2sin%5E2%28x%29cos%5E2%28x%29\"\r\n" );
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document.write( "Edwin
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