SOLUTION: How do you do this question without a calculator? cot^2 90 - sec^2 180 + csc^2 135

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Question 1109011: How do you do this question without a calculator?
cot^2 90 - sec^2 180 + csc^2 135
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
cotangent of 90 is cos 90/sin 90 or 0
sec^2 of 180 is 1/cos^2 180 and cos of 180 is -1, so this is 1
csc^2 of 135 is 1/ sin ^2 135 or 2/sqrt(2) * 2/sqrt(2)=2
0-(1)+2=1
One needs to know the sine and cosine of 45 (sqrt(2))/2, the cosine of 180 and the cosine of 90.