document.write( "Question 864465: 1.Solve the equation 2cos x-1=0, 0\n" ); document.write( "\n" ); document.write( "2. Solve the equation (cos^2)x-(sin^2)x=cos x, 0\n" ); document.write( "

Algebra.Com's Answer #521160 by stanbon(75887) $\"\"$ $\"About$

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1.Solve the equation
\n" ); document.write( "2cos x-1=0
\n" ); document.write( "cos(x) = 1/2
\n" ); document.write( "-----
\n" ); document.write( "x = pi/3 or x = -pi/3
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\n" ); document.write( "\n" ); document.write( "2. Solve the equation (cos^2)x-(sin^2)x=cos x, 0
\n" ); document.write( "2cos^2(x)-1 = cos(x)
\n" ); document.write( "-----
\n" ); document.write( "2cos^2(x) - cos(x) -1 = 0
\n" ); document.write( "-------
\n" ); document.write( "cos(x) = [-1 +- sqrt(1-4*2*-1)]/4
\n" ); document.write( "-------
\n" ); document.write( "cos(x) = [-1 +- 3]/4
\n" ); document.write( "---
\n" ); document.write( "cos(x) = -3/4 or cos(x) = 1/2
\n" ); document.write( "------
\n" ); document.write( "x = arccos(-3/4) or cos(x) = 1/2
\n" ); document.write( "-------
\n" ); document.write( "x = 138.59 or x = 60 degrees
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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