document.write( "Question 983506: Please help me solve these 3 equations for solutions from [0, 2pi]:\r
\n" ); document.write( "\n" ); document.write( "1.) \"2cos%5E2%282x%29-cos2x=0\"\r
\n" ); document.write( "\n" ); document.write( "2.) \"2sin%5E2%28x%29-sin%28x%29-1=0\"\r
\n" ); document.write( "\n" ); document.write( "3.) \"tan%5E2%283x%29=-tan%283x%29\"\r
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Algebra.Com's Answer #604333 by ikleyn(52803)\"\" \"About 
You can put this solution on YOUR website!
\r
\n" ); document.write( "\n" ); document.write( "1. \"2cos%5E2%282x%29\" - \"cos%282x%29\" = \"0\".\r
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\n" ); document.write( "\n" ); document.write( "Introduce new variable   \"y\" = \"cos%282x%29\". \r
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\n" ); document.write( "\n" ); document.write( "Then your equation will be \r
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\n" ); document.write( "\n" ); document.write( "\"2y%5E2\" - \"y\" = \"0\". \r
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\n" ); document.write( "\n" ); document.write( "One solution is  \"y\" = \"0\",  i.e.   \"cos%282x%29\" = \"0\",  which gives   \"2x\" = \"pi%2F2\"  or   \"2x\" = \"3pi%2F2\". \r
\n" ); document.write( "\n" ); document.write( "Please complete this case yourself.\r
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\n" ); document.write( "\n" ); document.write( "Next,  if  \"y\" is not zero,  then you can reduce the original equation to the form \r
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\n" ); document.write( "\n" ); document.write( "\"2y\" - \"1\" = \"0\",   i.e.   \"2cos%282x%29\" = \"1\".\r
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\n" ); document.write( "\n" ); document.write( "It gives you   \"cos%282x%29\" = \"1%2F2\",  and then   \"2x\" = \"pi%2F3\"  or   \"2x\" = \"2pi+-+pi%2F3\" = \"5pi%2F3\". \r
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\n" ); document.write( "\n" ); document.write( "You can complete this case yourself. \r
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\n" ); document.write( "\n" ); document.write( "The remaining equations can be solved using the same trick with introduction of a new variable. \r
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\n" ); document.write( "\n" ); document.write( "You can do it yourself.\r
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\n" ); document.write( "\n" ); document.write( "Good luck !!!\r
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