# Math Help - Finding trig functions.

1. ## Finding trig functions.

Hi, I'm having trouble with this problem. I'm supposed to find the trig functions. If I can have some help on part a I think I can do the rest on my own.

1. Suppose that
cosθ =−1/3, where π <θ < 3π/2.
Find and simplify the following. Draw a picture to help explain your answer.

a)
tanθ

I was able to draw a picture and determine that the point lies in quadrant 3. Do I need to use a pythagorean equation to find sinθ and then use that to find tanθ?

2. ## Re: Finding trig functions.

FatimaA
your question is not clear....are you trying to solve the trigonometric equations cosθ =1/3 and sina = 4/5....please explain.

3. ## Re: Finding trig functions.

Hi Minoanman. I'm trying to solve the trig functions for cosθ = -1/3 for now. Sinα =−4/5 is a different point on the circle. I'll edit that out of the OP so it's less confusing.

4. ## Re: Finding trig functions.

Fatima A
Please use correct language for mathematics...you are trying to solve a trigonometric equation...not a function!!!
anyway cosθ = -1/3 has a solution θ = 109.5 degrees..use a scientific calculator it is easy.... don't forget to limit your solutions only into the interval given .

5. ## Re: Finding trig functions.

Minoanman, I'm trying to find tanθ where cosθ = -1/3 and where π <θ < 3π/2. Sorry that wasn't clear.