document.write( "Question 86730: please help me solve this equation: cos 4x=sin2x from 0 to 360 degress. \n" ); document.write( "
Algebra.Com's Answer #62759 by stanbon(75887)\"\" \"About 
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solve this equation: cos 4x=sin2x from 0 to 360 degrees
\n" ); document.write( "--------
\n" ); document.write( "cos(4x) = cos^2(2x)-sin^2(2x)
\n" ); document.write( "cos^2(2x) = 1-sin^2(2x)
\n" ); document.write( "--------
\n" ); document.write( "Therefore your equation can be written:
\n" ); document.write( "cos^2(2x)-sin^2(2x)=sin2x
\n" ); document.write( "[1-sin^2(2x)] - sin^2(2x) = sin(2x)
\n" ); document.write( "2sin^2(2x)+sin(2x)-1=0
\n" ); document.write( "(2sin(2x)-1)(sin(2x)+1)=0
\n" ); document.write( "2sin(2x)=1 or sin(2x)=-1
\n" ); document.write( "sin(2x)=1/2 or sin(2x)=-1
\n" ); document.write( "2x=30 degrees or 150 degrees; 2x= 210 degrees or 330 degrees
\n" ); document.write( "x=15 degrees or 75 degrees; x=105 degrees or 165 degrees
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\n" ); document.write( "If the restricion \"from 0 to 360\" refers to the x value,
\n" ); document.write( "there are addtional solutions. I have made the assumption
\n" ); document.write( "the restriction refers to 2x.
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\n" ); document.write( "Cheers,
\n" ); document.write( "stan H. \n" ); document.write( "
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