document.write( "Question 243254: Prove that the following equation is an identity\r
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Algebra.Com's Answer #178218 by Edwin McCravy(20060)\"\" \"About 
You can put this solution on YOUR website!
\"4sin%28x%2F4%29cos%28x%2F4%29cos%28x%2F2%29=sin%28x%29\"
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document.write( "Write the \"4\" in the left side as \"2%2A2\"\r\n" );
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document.write( "\"2%2A2sin%28x%2F4%29cos%28x%2F4%29cos%28x%2F2%29=sin%28x%29\"\r\n" );
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document.write( "Put parentheses around \"2sin%28x%2F4%29cos%28x%2F4%29\"\r\n" );
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document.write( "\"2%2A%282sin%28x%2F4%29cos%28x%2F4%29%29cos%28x%2F2%29=sin%28x%29\"\r\n" );
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document.write( "Use the identity \"sin%282alpha%29=2sin%28alpha%29cos%28alpha%29\"\r\n" );
document.write( "using \"alpha=x%2F4\", \"sin%282%2A%28x%2F4%29%29=2sin%28x%2F4%29cos%28x%2F4%29\"\r\n" );
document.write( "or \"sin%28x%2F2%29=2sin%28x%2F4%29cos%28x%2F4%29\"\r\n" );
document.write( "to replace what we just put in parentheses:\r\n" );
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document.write( "\"2%2A%28sin%28x%2F2%29%29cos%28x%2F2%29=sin%28x%29\"\r\n" );
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document.write( "\"2sin%28x%2F2%29cos%28x%2F2%29=sin%28x%29\"\r\n" );
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document.write( "Now use that same identity again, \"sin%282alpha%29=2sin%28alpha%29cos%28alpha%29\",\r\n" );
document.write( "this time using \"alpha=x%2F2\", \"sin%282%2A%28x%2F2%29%29=2sin%28x%2F2%29cos%28x%2F2%29\"\r\n" );
document.write( "or \"sin%28x%29=2sin%28x%29cos%28x%29\" to replace the left side:\r\n" );
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document.write( "\"sin%28x%29=sin%28x%29\"\r\n" );
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document.write( "Edwin
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