document.write( "Question 602425: Verify that the equation is an identity:\r
\n" ); document.write( "\n" ); document.write( "sin^4 - cos^4 = 2sin^2 - 1\r
\n" ); document.write( "\n" ); document.write( "Also please show the steps if you can. It will be a lot of help since I'm not at all good with Math. Thank you! :) \n" ); document.write( "

Algebra.Com's Answer #380223 by jim_thompson5910(35256) $\"\"$ $\"About$

You can put this solution on YOUR website!
sin^4 - cos^4 = 2sin^2 - 1\r
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\n" ); document.write( "\n" ); document.write( "(sin^2)^2 - (cos^2)^2 = 2sin^2 - 1\r
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\n" ); document.write( "\n" ); document.write( "(sin^2-cos^2)(sin^2+cos^2) = 2sin^2 - 1\r
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\n" ); document.write( "\n" ); document.write( "(sin^2-cos^2)(1) = 2sin^2 - 1\r
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\n" ); document.write( "\n" ); document.write( "sin^2-cos^2 = 2sin^2 - 1\r
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\n" ); document.write( "\n" ); document.write( "sin^2 - (1 - sin^2) = 2sin^2 - 1\r
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\n" ); document.write( "\n" ); document.write( "sin^2 - 1 + sin^2 = 2sin^2 - 1\r
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\n" ); document.write( "\n" ); document.write( "2sin^2 - 1 = 2sin^2 - 1\r
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\n" ); document.write( "\n" ); document.write( "So this verifies the identity. \n" ); document.write( "

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