document.write( "Question 180127: Evaluate sin 390 degrees + cos (-45 degrees)-sin(-225 degrees) \n" ); document.write( "

Algebra.Com's Answer #134979 by Mathtut(3670) $\"\"$ $\"About$

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sin 390 or sin 30 degrees is 1/2
\n" ); document.write( "cos -45 or cos 45 degrees is $\"sqrt%282%29%2F2\"$
\n" ); document.write( "sin -225 or sin 45 degrees is $\"sqrt%282%29%2F2\"$
\n" ); document.write( ":
\n" ); document.write( "so 1/2+ $\"sqrt%282%29%2F2\"$ - $\"sqrt%282%29%2F2\"$
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\n" ); document.write( "=1/2 \n" ); document.write( "

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