document.write( "Question 870609: Find all solutions in the interval [0, 2pi) for the equation sin^2θ=cos^2θ-1 \n" ); document.write( "
Algebra.Com's Answer #525009 by jim_thompson5910(35256)\"\" \"About 
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I'm going to use the variable x instead of the variable θ\r
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\n" ); document.write( "\n" ); document.write( "Solve for x\r
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\n" ); document.write( "\n" ); document.write( "sin^2(x)=cos^2(x)-1
\n" ); document.write( "sin^2(x)-cos^2(x) = -1
\n" ); document.write( "-1(-sin^2(x)+cos^2(x)) = -1
\n" ); document.write( "-sin^2(x)+cos^2(x) = 1
\n" ); document.write( "cos^2(x)-sin^2(x) = 1
\n" ); document.write( "cos(2x) = 1
\n" ); document.write( "2x = arccos(1)
\n" ); document.write( "2x = 0+2pi*n
\n" ); document.write( "2x = 2pi*n
\n" ); document.write( "x = 2pi*n/2
\n" ); document.write( "x = pi*n\r
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\n" ); document.write( "\n" ); document.write( "All solutions for x are generated by x = pi*n where n is an integer\r
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\n" ); document.write( "\n" ); document.write( "If n = -1, then
\n" ); document.write( "x = pi*n
\n" ); document.write( "x = pi*(-1)
\n" ); document.write( "x = -pi ... not in the interval [0, 2pi), so we ignore it\r
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\n" ); document.write( "\n" ); document.write( "If n = 0, then
\n" ); document.write( "x = pi*n
\n" ); document.write( "x = pi*0
\n" ); document.write( "x = 0\r
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\n" ); document.write( "\n" ); document.write( "If n = 1, then
\n" ); document.write( "x = pi*n
\n" ); document.write( "x = pi*1
\n" ); document.write( "x = pi\r
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\n" ); document.write( "\n" ); document.write( "If n = 2, then
\n" ); document.write( "x = pi*n
\n" ); document.write( "x = pi*2
\n" ); document.write( "x = 2pi ... not in the interval [0, 2pi), so we ignore it\r
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\n" ); document.write( "\n" ); document.write( "The only two solutions are x = 0, x = pi (both in radians)
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