# Math Help - Inverse of Trig functions

1. ## Inverse of Trig functions

Write the expression and evaluate. There is only one answer whIch should match the range of the inverse trig function.

Sec^-1(-2)
Tan^-1(sqrt3)

2. ## Re: Inverse of Trig functions

You have to know some special angles, if not use your calculator.
But you have to know $-1\leq \cos(x) \leq 1$.

3. ## Re: Inverse of Trig functions

I know the angles to the unit circle and all, but this is supposed to be a non-calculator problem.

4. ## Re: Inverse of Trig functions

If you know the special angles then you should be able to calculate $\arctan(\sqrt{3})$.
What do you think about the first one? (look at the hint I gave you)

5. ## Re: Inverse of Trig functions

Arctan is the inverse of tan, so I guess if arctan= √(3) the. Tan = 1/√(3)? But yoi can't have √(3) Asa denominator, so do you multiply to make it √(3)/3?
Then again that could be completely wrong.

6. ## Re: Inverse of Trig functions

Originally Posted by crazycarlos61
Arctan is the inverse of tan, so I guess if arctan= √(3) the. Tan = 1/√(3)? But yoi can't have √(3) Asa denominator, so do you multiply to make it √(3)/3?
Then again that could be completely wrong.
it is. ... an inverse is not a reciprocal.

since $\tan\left(\frac{\pi}{3}\right) = \sqrt{3}$ , then $\arctan(\sqrt{3}) = \frac{\pi}{3}$

you need to review what an inverse function does.

7. ## Re: Inverse of Trig functions

Ah, thank you for telling me the definition.