# Thread: Trigonometry math help.. confirmation?

1. ## Trigonometry math help.. confirmation?

i been trying to solve this but can't seem to get the wrong answer, can anyone help me located where i went wrong?

3cot^2(x)=1 , x is greater than or equal to 0 and less than 2pi

cot(x) = 1/square root 3

x = 60 degree or pi / 3

shouldn't the 4 answers be pi/3, -2pi/3, 4pi/3, and -5pi/3
correct me if im wrong please. thank you!

2. Originally Posted by ASUSpro
i been trying to solve this but can't seem to get the wrong answer, can anyone help me located where i went wrong?

3cot^2(x)=1 , x is greater than or equal to 0 and less than 2pi

cot(x) = 1/square root 3

x = 60 degree or pi / 3

shouldn't the 4 answers be pi/3, -2pi/3, 4pi/3, and -5pi/3
correct me if im wrong please. thank you!
Two of these are correct. Note that your solution set needs to be $\displaystyle 0 \leq \theta < 2 \pi$. What does this do to your negative solutions?

-Dan

3. I can't add 360 degree , that wil make them out of range, do i just remove the negative signs?

4. Originally Posted by ASUSpro
I can't add 360 degree , that wil make them out of range, do i just remove the negative signs?
The solution $\displaystyle -2 \pi /3$ is in QIII, so we have a reference angle of $\displaystyle \pi /3$ below the -x axis. Thus the angle $\displaystyle -2 \pi /3$ is the same as $\displaystyle \pi + \pi / 3 = 4 \pi / 3$ which is already on your list.

-Dan