document.write( "Question 409940: Hi, please help me with this problem:\r
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Algebra.Com's Answer #288423 by richard1234(7193)\"\" \"About 
You can put this solution on YOUR website!
Cosine and arccosine are inverse functions, so \"cos%28arccos%28-1%2F2%29%29+=+-1%2F2\". \n" ); document.write( "
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