document.write( "Question 627391: Use an algebraic method to find the exact solution(s) for sin 2x = sin x, where 0 is less than or equal to x which is less than 2 pie (Please show work) \n" ); document.write( "
Algebra.Com's Answer #394911 by hammy(9)![]() ![]() You can put this solution on YOUR website! sin 2x=sin x \n" ); document.write( "sin(x+y)=sinx*cosy+siny*cosx \n" ); document.write( "so, sin 2x or sin(x+x)=2sinxcosx \n" ); document.write( "Substitute \n" ); document.write( "2sinxcosx=sinx \n" ); document.write( "2sinxcosx-sinx=0 \n" ); document.write( "sinx(2cosx-1)=0 \n" ); document.write( "By the zero product property \n" ); document.write( "sinx=0 and 2cosx-1=0\r \n" ); document.write( "\n" ); document.write( "sinx=0 when x=0,pie\r \n" ); document.write( "\n" ); document.write( "2cosx-1=0 \n" ); document.write( "2cosx=1 \n" ); document.write( "cosx=1/2 when x=pie/3,5*pie/3 \n" ); document.write( " |