Question

find the value of csc Ɵ, if cos Ɵ=-2/3; 180 degrees<Ɵ<270 degrees

Answer 1

by definition, cosecant theta is equal to 1 over cosine theta

Answer 2

When I worked it out I keep getting -3/2 is this correct?

Answer 3

Yes.

Answer 4

one more thing is the exact value of cos2theta if sin theta =-square root5/3 and 180 degree<Ɵ<270 degree. I'm getting -1/9 is this correct?

Answer 5

substitute the value of sin theta in cos 2 theta forumla and you should get the correct answer.

Answer 6

It has been a while since I did high school trigonometry. I don't remember all the formulas

Answer 7

okay I redid it and I got -4squareroot5/9

Answer 8

Sorry, can't really help you there.

Answer 9

thanks for trying! :)