document.write( "Question 978446: Solve the equation for the interval [0,2π)\r
\n" ); document.write( "\n" ); document.write( "cos²(x)+2cos(x)+1 = 0\r
\n" ); document.write( "\n" ); document.write( "The answer I know that is: π , but how to you do it? \n" ); document.write( "

Algebra.Com's Answer #599843 by Edwin McCravy(20060) $\"\"$ $\"About$

You can put this solution on YOUR website!

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document.write( "Use u-substitution:\r\n" );
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document.write( "Let u = cos(x)\r\n" );
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document.write( "u+1 = 0\r\n" );
document.write( "  u = -1\r\n" );
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document.write( "Substitute cos(x) for u\r\n" );
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document.write( "cos(x) = -1\r\n" );
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document.write( "     x = p\r\n" );
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document.write( "Edwin

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