document.write( "Question 1077073: How do I go about proving this identity?: \r
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\n" ); document.write( "\n" ); document.write( "I've been looking up sites and asking friends but I just don't understand this. \n" ); document.write( "
Algebra.Com's Answer #691638 by Edwin McCravy(20065)\"\" \"About 
You can put this solution on YOUR website!
\"1%2Btan%28x%29tan%28x%2F2%29\"\"%22%22=%22%22\"\"sec%28x%29\"\r\n" );
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document.write( "Are you familiar with this half-angle identity? \r\n" );
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document.write( "\"tan%28x%2F2%29\"\"%22%22=%22%22\"\"%281-cos%28x%29%29%2Fsin%28x%29\"\r\n" );
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document.write( "That substitution makes it easy.  But if you still have \r\n" );
document.write( "trouble proving the identity after using that, tell me\r\n" );
document.write( "about it in the thank-you note form below and\r\n" );
document.write( "I'll get back to you by email. (No charge ever!)\r\n" );
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document.write( "Edwin
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