document.write( "Question 1001690: 2sin^2x=3sinx+5
\n" ); document.write( "solve equation on interval [0,2pi)
\n" ); document.write( "

Algebra.Com's Answer #618770 by ikleyn(52873)\"\" \"About 
You can put this solution on YOUR website!
.
\n" ); document.write( "\"2%2Asin%5E2%28x%29\" = \"3%2Asin%28x%29\" + \"5\".\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Let us introduce a new variable,  y = sin(x).\r
\n" ); document.write( "\n" ); document.write( "Then the equation takes the form\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"2y%5E2\" = \"3y+%2B+5\",     or\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"2y%5E2\" - \"3y\" - \"5\" = \"0\".\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Solve it by using the quadratic formula:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y%5B1%2C2%5D\" = \"%283+%2B-+sqrt%283%5E2+%2B+4%2A2%2A5%29%29%2F4\" = \"%283+%2B-+sqrt%2849%29%29%2F4\" = \"%283+%2B-+7%29%2F4\".\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y%5B1%5D\" = -1   ----->   sin(x) = -1   ----->   x = \"3%2Api%2F2\".\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y%5B2%5D\" = \"10%2F4\"  doesn't fit,  because  sin(x)  can not be more than  1.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Answer.  x = \"3%2Api%2F2\".\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );