document.write( "Question 261459: How do you find the cos of 55 degrees using the sum and difference identity?
\n" ); document.write( " cos (x + y) = (cos x) (cos y) - (sin x) (sin y) and
\n" ); document.write( " cos (x - y) = (cos x) (cos y) + (sin x) (sin y)\r
\n" ); document.write( "\n" ); document.write( " I can't find 2 angles that add or subtract to get 55.
\n" ); document.write( " Ex: 315 - 270 = 45 degrees, not 55
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Algebra.Com's Answer #192639 by Edwin McCravy(20060)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "There aren't any special angles that will give 55°.\r\n" );
document.write( "I suspect that the problem was a book typo, and\r\n" );
document.write( "should have been 75°, perhaps, which could have\r\n" );
document.write( "geen gotten with 45°+30°\r\n" );
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document.write( "Edwin
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