# Thread: Terminal arm

1. ## Terminal arm

The point (-2,3) lies on the terminal arm of position angle

I dont know how to solve this question, I had one where it was simular but gave an equation like y=cotx and I couldnt solve that either.

I know sin=3 and cos=-2 but that is it.

2. Originally Posted by brentwoodbc
The point (-2,3) lies on the terminal arm of position angle

I dont know how to solve this question, I had one where it was simular but gave an equation like y=cotx and I couldnt solve that either.
I still don't know your question. If you're trying to find $\displaystyle \cot \theta$, then the answer would be $\displaystyle -\frac{2}{3}$, because in the cartesian plane, with point (x, y) on the terminal ray, $\displaystyle \cot \theta = \frac{x}{y}$.

I know sin=3 and cos=-2 but that is it.
First, watch your notation. You can't write a trig function without an angle. You must write something like
$\displaystyle \sin \theta = 3$ or $\displaystyle \cos \theta = -2$.
Second, neither value is possible. Sine or cosine of any angle will be between -1 and 1 inclusive. If you're using the point (x, y) to figure out sine and cosine, you need these definitions:
$\displaystyle \sin \theta = \frac{y}{r}$ and
$\displaystyle \cos \theta = \frac{x}{r}$.

In other words, you forgot to divide each by r. (r is easy to find, it's just $\displaystyle \sqrt{x^2 + y^2}$).

01

3. Originally Posted by brentwoodbc
The point (-2,3) lies on the terminal arm of position angle

answer is given is

Thats my question how do you solve that.

4. Originally Posted by brentwoodbc
Thats my question how do you solve that.
What you have posted is not clear enough to answer.

5. I know that is what I thought but it is like question #31 then that.