document.write( "Question 1093373: 3sinx+4cosx=5 \n" ); document.write( "
Algebra.Com's Answer #708003 by ikleyn(52879)\"\" \"About 
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document.write( "3sin(x) + 4cos(x) = 5  ---> \r\n" );
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document.write( "\"%283%2F5%29%2Asin%28x%29+%2B+%284%2F5%29%2Acos%28x%29\" = 1.\r\n" );
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document.write( "Let \"a\" be the angle in QI such that cos(a) = \"3%2F5\",  sin(a) = \"4%2F5\".\r\n" );
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document.write( "Such an angle does exists since \"%283%2F5%29%5E2+%2B+%284%2F5%29%5E2\" = 1.\r\n" );
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document.write( "Then \r\n" );
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document.write( "1 = \"%283%2F5%29%2Asin%28x%29+%2B+%284%2F5%29%2Acos%28x%29\" = cos(a)*sin(x) + sin(a)*cos(x) = sin(a+x) = sin(x+a).\r\n" );
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document.write( "It implies that x + a = \"pi%2F2\" and, hence, x = \"pi%2F2-a\",  where a = \"arcsin%284%2F5%29\"\r\n" );
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\n" ); document.write( "\n" ); document.write( "Answer.   x = \"pi%2F2-arcsin%284%2F5%29\".\r
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