document.write( "Question 733332: Solve 2 sin^2 x + cos x -2=0 on the interval -pi< x < pi \n" ); document.write( "

Algebra.Com's Answer #448509 by lwsshak3(11628) $\"\"$ $\"About$

You can put this solution on YOUR website!
Solve 2 sin^2 x + cos x -2=0 on the interval 0 < x < 2π
\n" ); document.write( "2 sin^2 x + cos x -2=0
\n" ); document.write( "2(1-cos^2x)+cosx-2=0
\n" ); document.write( "2-2cos^2x+cosx-2=0
\n" ); document.write( "-2cos^2x+cosx=0
\n" ); document.write( "cosx(1-2cosx)=0
\n" ); document.write( "cosx=0
\n" ); document.write( "x=π/2, 3π/2
\n" ); document.write( "or
\n" ); document.write( "1-2cosx=0
\n" ); document.write( "2cosx=1
\n" ); document.write( "cosx=1/2
\n" ); document.write( "x=π/6, 11π/6 (in Q1 and Q4 where cos>0) \n" ); document.write( "

\n" );