document.write( "Question 1119399: proving compound angle formula
\n" ); document.write( "a) tan(x+45)-tan(x-45)= 4tanx/1-tan^2x\r
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\n" ); document.write( "\n" ); document.write( "b) sin(x-30)-cos(x+60)=square root 3sinx-cos x\r
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Algebra.Com's Answer #734975 by Edwin McCravy(20060)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "That's not true, for if you substitute x = 100°,\r\n" );
document.write( "you get 45.71229319 = -3.585054968, so\r\n" );
document.write( "you must have copied it wrong.\r\n" );
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document.write( "But the second one is true:\r\n" );
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document.write( "\"sin%28x-%2230%B0%22%29-cos%28x%2B%2260%B0%22%29=sqrt%283%29%2Asin%28x%29-cos%28x%29+\"\r\n" );
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document.write( "Work with left side only:\r\n" );
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document.write( "\"sin%28x-%2230%B0%22%29-cos%28x%2B%2260%B0%22%29+\"\r\n" );
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document.write( " \r\n" );
document.write( "\"sqrt%283%29%2Asin%28x%29-cos%28x%29\"\r\n" );
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document.write( "Edwin
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