document.write( "Question 591078: How can I prove this identity? (1-cos^2theta)(1+cos^2theta)=2sin^2theta-sin^4theta?\r
\n" ); document.write( "\n" ); document.write( "I tried to do it, and this is what I've come up with so far, and am not sure if I am doing it correctly.\r
\n" ); document.write( "\n" ); document.write( "Working with the left side, I have the following:\r
\n" ); document.write( "\n" ); document.write( "sin^2theta(1+cos^2theta) = \r
\n" ); document.write( "\n" ); document.write( "sin^2theta+(sin^2theta*cos^2theta)\r
\n" ); document.write( "\n" ); document.write( "And then it stops.
\n" ); document.write( " \n" ); document.write( "
Algebra.Com's Answer #375479 by Alan3354(69443)\"\" \"About 
You can put this solution on YOUR website!
How can I prove this identity? (1-cos^2theta)(1+cos^2theta)=2sin^2theta-sin^4theta?\r
\n" ); document.write( "\n" ); document.write( "I tried to do it, and this is what I've come up with so far, and am not sure if I am doing it correctly.\r
\n" ); document.write( "\n" ); document.write( "Working with the left side, I have the following:\r
\n" ); document.write( "\n" ); document.write( "sin^2theta(1+cos^2theta) = \r
\n" ); document.write( "\n" ); document.write( "sin^2theta+(sin^2theta*cos^2theta)
\n" ); document.write( "---------------
\n" ); document.write( "(1-cos^2theta)(1+cos^2theta)=2sin^2theta-sin^4theta?
\n" ); document.write( "sin^2(t)*(1+cos^2theta)=2sin^2theta - sin^4theta?
\n" ); document.write( "(1+cos^2theta) = 2 - sin^2theta?
\n" ); document.write( "1+cos^2theta + sin^(t) = 2
\n" ); document.write( "cos^2(t) + sin^(t) = 1
\n" ); document.write( "I'm convinced.
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