document.write( "Question 1104682: (sinx+cosx)²=3/4.Find cos²2x. \n" ); document.write( "

Algebra.Com's Answer #719371 by greenestamps(13200) $\"\"$ $\"About$

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\n" ); document.write( "(1) Expand the expression on the left in the given equation.

\n" ); document.write( " $\"%28sinx%2Bcosx%29%5E2+=+sinx%5E2%2B2sinx%2Acosx%2Bcosx%5E2+=+1%2B2sinx%2Acosx+=+1%2Bsin2x\"$

\n" ); document.write( "Then
\n" ); document.write( " $\"1%2Bsin2x+=+3%2F4\"$
\n" ); document.write( " $\"sin2x+=+-1%2F4\"$

\n" ); document.write( "Then find (cos(2x))^2 using $\"%28sin%282x%29%29%5E2%2Bcos%282x%29%5E2+=+1\"$ \n" ); document.write( "

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