document.write( "Question 964726: prove 2sin(2x)(1-2sin^2x)=sin(4x) \n" ); document.write( "
Algebra.Com's Answer #589570 by t0hierry(194)\"\" \"About 
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sin(4x) = 2 sin(2x) cos(2x)
\n" ); document.write( " = 2 sin(2x) (1-2 sin^2 x)\r
\n" ); document.write( "\n" ); document.write( "using
\n" ); document.write( "cos(2x) = cos(x+x) = cos^2(x) - sin^2(x) = 1-2 sin^2 x
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