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You can put this solution on YOUR website!
Hi there,
\n" ); document.write( "((cos2A)/(cosA+sinA)^3) = (cosA-sinA)/(1+sin2A)
\n" ); document.write( "Take each part separately. Leave the right hand side as
\n" ); document.write( "the answer you are aiming for.
\n" ); document.write( "cos2A we are going to use cos^2A - sin^2A
\n" ); document.write( "Next we look at (cosA + sinA)^3
\n" ); document.write( "First we square (cosA + sinA)^2
\n" ); document.write( "= (cos^2A +2sinAcosA + sin^2A)
\n" ); document.write( "Consider (cos^2A +2sinAcosA + sin^2A)
\n" ); document.write( "(cos^2A + sin^2A = 1)
\n" ); document.write( "(2sinAcosA = sin2A)
\n" ); document.write( "So (cos^2A +2sinAcosA + sin^2A)
\n" ); document.write( "goes down to (1 + sin2A)
\n" ); document.write( "Next we still have (cosA + sinA)
\n" ); document.write( "to multiply into it, so we place it
\n" ); document.write( "next to the (1 + sin2A)
\n" ); document.write( "Our Left Hand side =
\n" ); document.write( "sin^2A - cos^2A/ (sinA + cosA)(1 + sin2A) = RHS.
\n" ); document.write( "Now divide (sinA + cosA) on bottom
\n" ); document.write( "into cos^2A - sin^2A on top
\n" ); document.write( "This gives you:
\n" ); document.write( "(cosA - sinA)/(1 + sin2A) = RHS.
\n" ); document.write( "Hope this helps
\n" ); document.write( "Sorry it is so long winded!
\n" ); document.write( "All the best :-) \n" ); document.write( "