document.write( "Question 888438: How to: \"Find the number of solutions of the equation cos^2-1=0 in the interval [0, 2pi]\r
\n" ); document.write( "\n" ); document.write( "I began by using the Pythagorean identity and replaced cos^2 by (1-sin^2x).
\n" ); document.write( "The problem then looked like: (1-sin^2x)-1=0. \r
\n" ); document.write( "\n" ); document.write( "I canceled out the 1 & -1 making the problem: -sin^2=0\r
\n" ); document.write( "\n" ); document.write( "I do not know where to go from here, or if I have been doing the problem right so far. \n" ); document.write( "

Algebra.Com's Answer #537412 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
You're alright up to there although you could have just stayed with cosine.
\n" ); document.write( " $\"-sin%5E2%28x%29=0\"$
\n" ); document.write( "Multiply both sides by (-1).
\n" ); document.write( " $\"sin%5E2%28x%29=0\"$
\n" ); document.write( "Take the square root of both sides.
\n" ); document.write( " $\"sin%28x%29=0\"$
\n" ); document.write( "Now, which values of $\"x\"$ give you a value of $\"0\"$ ?
\n" ); document.write( "There are two of them.
\n" ); document.write( " $\"x=0\"$
\n" ); document.write( "and
\n" ); document.write( " $\"x=pi\"$
\n" ); document.write( ".
\n" ); document.write( ".
\n" ); document.write( ".
\n" ); document.write( "For the cosine,
\n" ); document.write( " $\"cos%5E2%28x%29-1=0\"$
\n" ); document.write( " $\"cos%5E2%28x%29=1\"$
\n" ); document.write( " $\"cos%28x%29=0+%2B-+1\"$
\n" ); document.write( "Also, two solutions.
\n" ); document.write( " $\"x=0\"$ and
\n" ); document.write( " $\"x=pi\"$
\n" ); document.write( " \n" ); document.write( "

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