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05-04-2012, 01:50 PM   #5
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Status: Pre-Dental
Join Date: Jun 2008
Posts: 240

Quote:
 Originally Posted by Dgeorg6 tan = sin/cos so d is not true because 295 is in the 3rd quadrant and as you have already written, cos is + in the 3rd quadrant meaning it is >0 not <0

In high school, I remembered this by ASTC - All Students Take Calculus. Starting from the top right quadrant, and working counter clockwise. A=all, S=sin T=tan C=cos. Here's a picture.
http://media.wiley.com/Lux/49/184749.image0.jpg

If your doing this by finding the equivalent, it is a waste of time. Your thinking too hard.

Since your only dealing with 295 degree, you just need to realize it ends up in the 4th quadrant. In the 4th quadrant, cos are all positive, and thus sec is also positive since sec=1/cos.

d)cos 295<0 is saying that's a negative, but it should be positive from what I just said

Quote:
 Originally Posted by Member 8586 Chad to the rescue! well somewhat lol...ok so as for b,c,e: b) sec = 1/cos so 1/positive = positive? c) tan = sin/cos so negative/positive = negative? e) csc = 1/sin so 1/negative = negative?
For Cos 116, it lies in 2nd quad, where sin/csc are positive. So cos 116 is negative. That's how simple it is.

Last edited by KyoPhan; 05-04-2012 at 02:08 PM.