SOLUTION: what is sec of 225 degrees? I understand that its like -1.4 or something but I don't understand how to get there. Could you walk me through it? Thanks

Algebra ->  Trigonometry-basics -> SOLUTION: what is sec of 225 degrees? I understand that its like -1.4 or something but I don't understand how to get there. Could you walk me through it? Thanks      Log On


   

Question 1033656: what is sec of 225 degrees? I understand that its like -1.4 or something but I don't understand how to get there. Could you walk me through it?
Thanks
Answer by fractalier(6550) About Me  (Show Source):
You can put this solution on YOUR website!
The way I teach it is first to write that
sec 225 = 1/cos 225
Then look for the value of cos 225.
The reference angle is 45 degrees.
In the third quadrant, cosine is negative.
Thus cos 225 = -cos 45 = -sqrt(2)/2 which means
sec 225 = -2%2Fsqrt%282%29+=+-sqrt%282%29