document.write( "Question 605241: 1.Derive a formula for cos 2A with aid of cos (A + B).
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Algebra.Com's Answer #381598 by Edwin McCravy(20060)\"\" \"About 
You can put this solution on YOUR website!
1.Derive a formula for cos 2A with aid of
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document.write( "cos(A + B) = cos(A)cos(B) - sin(A)sin(B)\r\n" );
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document.write( "Substitute A for B\r\n" );
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document.write( "cos(A + A) = cos(A)cos(A) - sin(A)sin(A)\r\n" );
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document.write( "Simplifying,\r\n" );
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document.write( "cos(2A) = cosē(A) - sinē(A)\r\n" );
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document.write( "----------------------------\r\n" );
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\n" ); document.write( "2.Prove that \r
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document.write( "2·\"sin%28x%29%2Fcos%28x%29\" + 2·\"cos%28x%29%2Fsin%28x%29\"\r\n" );
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document.write( "\"2sin%28x%29%2Fcos%28x%29\" + \"2cos%28x%29%2Fsin%28x%29\"\r\n" );
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document.write( "Get LCD of sin(x)cos(x)\r\n" );
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document.write( "\"%282sin%5E2%28x%29+%2B+2cos%5E2%28x%29%29%2F%28sin%28x%29cos%28x%29%29\"\r\n" );
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document.write( "\"%282%28sin%5E2%28x%29+%2B+cos%5E2%28x%29%29%29%2F%28sin%28x%29cos%28x%29%29\"\r\n" );
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document.write( "\"%282%281%29%29%2F%28sin%28x%29cos%28x%29%29\"\r\n" );
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document.write( "\"+2%2F%28+sin%28x%29cos%28x%29+%29+\"\r\n" );
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document.write( "Multiply by \"2%2F2\"\r\n" );
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document.write( "\"4%2F%282sin%28x%29cos%28x%29%29\"\r\n" );
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document.write( "\"4%2Fsin%282x%29\"\r\n" );
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document.write( "Edwin
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