document.write( "Question 957695: What is the maximum and minimum of function y=cos4x-4cos2x+3 and its pi values
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Algebra.Com's Answer #585422 by Fombitz(32388) $\"\"$ $\"About$

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Take the derivative and set it equal to zero,
\n" ); document.write( " $\"dy%2Fdx=-4sin%284x%29%2B8sin%282x%29=0\"$
\n" ); document.write( "Solutions are when $\"x=n%2Api\"$ and $\"x=n%2A%28pi%2F2%29\"$
\n" ); document.write( "Then,
\n" ); document.write( "When $\"x=n%2Api\"$
\n" ); document.write( " $\"y%5Bmin%5D=1-4%2B3=0\"$
\n" ); document.write( "When $\"x=n%2A%28pi%2F2%29\"$
\n" ); document.write( " $\"y%5Bmax%5D=1%2B4%2B3=8\"$ \r
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