document.write( "Question 609385: How do you solve sin(x/2)-cosx=0 with a restriction of [0,2pi)? We are supposed to be using the half angle formula... \n" ); document.write( "
Algebra.Com's Answer #449605 by Barbazzo(2)\"\" \"About 
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\"cos+x-sin%28x%2F2%29+=+0\"
\n" ); document.write( "Transform Cos into Sin using Double Angle Identity: \"cos%282u%29+=+1-2sin%5E2%28u%29\"
\n" ); document.write( "Let \"u+=+x%2F2\", so \"cos%28x%29+=+1-2sin%5E2%28x%2F2%29\"
\n" ); document.write( "\"1-2sin%5E2%28x%2F2%29+-+sin%28x%2F2%29+=+0\"
\n" ); document.write( "\"-2sin%5E2%28x%2F2%29-sin%28x%2F2%29%2B1+=+0\"
\n" ); document.write( "\"2sin%5E2%28x%2F2%29%2Bsin%28x%2F2%29-1+=+0\"
\n" ); document.write( "Factor: \"%28sin%28x%2F2%29%2B1%29%282sin%28x%2F2%29-1%29+=+0\"
\n" ); document.write( "Split into two equations:
\n" ); document.write( "\"sin%28x%2F2%29%2B1+=+0\" and \"2sin%28x%2F2%29-1+=+0\"
\n" ); document.write( "For \"sin%28x%2F2%29%2B1+=+0\":
\n" ); document.write( "\"sin%28x%2F2%29+=+-1\"
\n" ); document.write( "Take the inverse Sin:
\n" ); document.write( "\"x%2F2+=+2n%2Api-pi%2F2\", where n is an integer
\n" ); document.write( "\"x+=+4n%2Api-pi\", so no value of n is within the restriction 0 to \"2pi\"
\n" ); document.write( "not even n=0, since \"x+=+-pi\"
\n" ); document.write( "NOTE: x can't equal positive \"pi\" since \"sin%28pi%2F2%29+%3C%3E+-1\"
\n" ); document.write( "and the given equation: \"sin%28x%2F2%29-cos%28x%29=0\" would not be true!\r
\n" ); document.write( "\n" ); document.write( "For \"2sin%28x%2F2%29-1+=+0\":
\n" ); document.write( "\"2sin%28x%2F2%29+=+1\"
\n" ); document.write( "\"sin%28x%2F2%29+=+1%2F2\"
\n" ); document.write( "Take the inverse Sin:
\n" ); document.write( "\"x%2F2+=+pi%2F6%2B2n%2Api\"
\n" ); document.write( "\"x+=+pi%2F3%2B4n%2Api\", n must = 0, else not within restriction, so \"x+=+pi%2F3\"
\n" ); document.write( "OR
\n" ); document.write( "\"x%2F2+=+5pi%2F6%2B2n%2Api\"
\n" ); document.write( "\"x+=+5pi%2F3%2B4n%2Api\", n must = 0, else not within restriction, so \"x+=+5pi%2F3\"\r
\n" ); document.write( "\n" ); document.write( "So all values of x within restriction 0 to \"2pi\" are:
\n" ); document.write( "(\"pi%2F3\", \"5pi%2F3\")
\n" ); document.write( "
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