# Understanding Tangent and Cotangent

1. Mar 5, 2015

### Tyrion101

I believe I understand both, for instance tangent is equal to y/x and so when you have something like root3/3 it would be equal to the points (root3/2 (x coordinate), and 1/2(y coordinate.) For Cotangent equal to zero, would be (0,1) and (0, -1) am I off base here? I think also that Cot is equal to x/y.

2. Mar 5, 2015

### SteamKing

Staff Emeritus
You can check your calculations here.

tan θ = y / x

If x = (√3) / 2 and y = 1 / 2, then what is y / x = ?

By definition, cot (θ) = 1 / tan (θ) = cos (θ) / sin (θ)

In order for cot (θ) = 0, this implies that cos (θ) = 0

For which values of θ does cos (θ) = 0? (Hint: check using the unit circle.)

3. Mar 5, 2015

### Tyrion101

When you take a root, you want both positive and negative answers on the unit circle yes?

4. Mar 5, 2015

### SteamKing

Staff Emeritus
That's irrelevant in this case.

Your specific example involved x = (√3) / 2 and y = 1 / 2.

If you do the arithmetic to calculate y / x, what number do you get?