document.write( "Question 474432: how do you Verify this equation?: sin(np + q) = (-1)nsin(q), where n is an integer \n" ); document.write( "
Algebra.Com's Answer #325383 by Edwin McCravy(20056)\"\" \"About 
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document.write( "It comes from the fact that \r\n" );
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document.write( "sin(np) = 0\r\n" );
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document.write( "and\r\n" );
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document.write( "cos(0p) = 1, cos(1p) = -1, cos(2p) = 1, cos(3p) = -1, cos(4p) = 1, etc.\r\n" );
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document.write( "cos([even number]·p) = 1,  cos([odd number]·p) = -1 \r\n" );
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document.write( "and\r\n" );
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document.write( "(-1)(even number) = 1,  (-1)(odd number) = -1\r\n" );
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document.write( "therefore, since even and odd numbers alternate, we have \r\n" );
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document.write( "cos(np) = (-1)n\r\n" );
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document.write( "---------------------------------------------\r\n" );
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document.write( "Therefore,\r\n" );
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document.write( "sin(np + q) = \r\n" );
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document.write( "sin(np)cos(q) + cos(np)sin(q) =\r\n" );
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document.write( "     0·cos(q) + (-1)nsin(q) =\r\n" );
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document.write( "                  (-1)nsin(q) \r\n" );
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document.write( "Edwin
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