document.write( "Question 750034: Please help me \r
\n" ); document.write( "\n" ); document.write( "Solve the following equation for x, if 0 ≤ x ≤ 2π\r
\n" ); document.write( "\n" ); document.write( "a) 2cos²θ + cosθ - 1 = 0\r
\n" ); document.write( "\n" ); document.write( "b) sin²θ - sinθ = 0\r
\n" ); document.write( "\n" ); document.write( "c) √58cos(θ + 0.78) = -6\r
\n" ); document.write( "\n" ); document.write( "Thanks \n" ); document.write( "

Algebra.Com's Answer #456314 by lwsshak3(11628) $\"\"$ $\"About$

You can put this solution on YOUR website!
Solve the following equation for x, if 0≤ x ≤ 2π
\n" ); document.write( "a) 2cos²θ + cosθ - 1 = 0
\n" ); document.write( "(2cosx-1)(cosx+1)=0
\n" ); document.write( "cosx=1/2
\n" ); document.write( "x=π/3, 5π/3
\n" ); document.write( "or cosx=-1
\n" ); document.write( "x=π
\n" ); document.write( "..
\n" ); document.write( "b) sin²θ - sinθ = 0
\n" ); document.write( "sinx(sinx-1)=0
\n" ); document.write( "sinx=0
\n" ); document.write( "x=0,π
\n" ); document.write( "sinx=1
\n" ); document.write( "x=π/2
\n" ); document.write( "..
\n" ); document.write( "c) √58cos(θ + 0.78) = -6
\n" ); document.write( "cos(x+.78)=-6/√58≈-0.79
\n" ); document.write( "cos^-1(-0.79)≈2.48 in Q2
\n" ); document.write( "x+.78=2.48
\n" ); document.write( "x=2.48-.78=1.7 \n" ); document.write( "

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