document.write( "Question 1033278: 2cos^2x + cosx = 0 \n" ); document.write( "

Algebra.Com's Answer #647834 by ikleyn(52814) $\"\"$ $\"About$

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\n" ); document.write( "2cos^2x + cosx = 0
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document.write( " +  = ,     (1)\r\n" );
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document.write( " = .      (2)\r\n" );
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document.write( "So, our equation (2) deploys in two equations:\r\n" );
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document.write( "1.  cosx) = 0  --->  x = ,  k = 0, +/-1, +/-2, . . . (3)\r\n" );
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document.write( "and\r\n" );
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document.write( "2.  2cos(x) + 1 = 0  --->  cos(x) =   --->  x = ,  k = 0, +/-1, +/-2, . . . (4)\r\n" );
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document.write( "                                        and/or  x = ,  k = 0, +/-1, +/-2, . . . (5)\r\n" );
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document.write( "The union of the three sets (3) U (4) U (5) is the set of solutions of the original equation (1).\r\n" );
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