document.write( "Question 433310: verify identinty
\n" ); document.write( "sec^4x – (tan^4x + sec^2x) = sec^2x · sin^2x
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Algebra.Com's Answer #300407 by Alan3354(69443)\"\" \"About 
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sec^4x – (tan^4x + sec^2x) = sec^2x · sin^2x
\n" ); document.write( "sec^4x – tan^4x - sec^2x) = sec^2x*sin^2x = sin^2/cos^2
\n" ); document.write( "Multiply thru by cos^4 and change to sines & cosines
\n" ); document.write( "1 - sin^4 - cos^2 = sin^2cos^2
\n" ); document.write( "sin^2 - sin^4 = sin^2cos^2
\n" ); document.write( "Divide by sin^2
\n" ); document.write( "1 - sin^2 = cos^2
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\n" ); document.write( "Always change everything to sines and cosines.
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