Answers

2015-05-28T00:51:25+05:30
cos 135 =cos(180-45) = -cos 45 = -1/√2
here, we get negative sign since the value of cos in 2nd quadrant is negative. since we change cos from 180, it remains as cos only without changing into sin
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2015-05-28T08:37:35+05:30
Cos 135 degrees = cos (90 +45) = - sin45 = - 1/√2 
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