document.write( "Question 966031: For sin2x+cosx=0, use a double-angle or half-angle formula to simplify the equation and then find all solutions of the equation in the interval [0,2π).
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Algebra.Com's Answer #590453 by lwsshak3(11628) $\"\"$ $\"About$

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For sin2x+cosx=0, use a double-angle or half-angle formula to simplify the equation and then find all solutions of the equation in the interval [0,2π).
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\n" ); document.write( "sin(2x)+cosx=0
\n" ); document.write( "2sinxcosx+cosx=0
\n" ); document.write( "cosx(2sinx+1)=0
\n" ); document.write( "cosx=0
\n" ); document.write( "x=π/2, 3π/2 (in quadrants I and II where sin>0)
\n" ); document.write( "or
\n" ); document.write( "2sinx+1=0
\n" ); document.write( "sinx=-1/2
\n" ); document.write( "x=7π/6, 11π/6 (in quadrants II and IV where sin<0) \n" ); document.write( "

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