# Thread: Half Angle of Tan

1. ## Half Angle of Tan

Given that tan(a)=-5/sqrt11, find the exact value of tan(a/2).

I'm getting , but it says I'm wrong?

2. ## Re: Half Angle of Tan Originally Posted by silentwhspr22 Given that tan(a)=-5/sqrt11, find the exact value of tan(a/2).

I'm getting , but it says I'm wrong?
Have a look at this.

3. ## Re: Half Angle of Tan

I still don't get it. I've been working on this problem for over an hour now and can't make it make sense.

4. ## Re: Half Angle of Tan Originally Posted by silentwhspr22 I still don't get it. I've been working on this problem for over an hour now and can't make it make sense.
The most "powerful computional" resource, wolframapha available , agrees with your answer: SEE HERE
That means you are giving the program a form of the answer that it does like or the program is just wrong. Your answer is correct and the form you are entering is not liked. This is a common problem with web-based mathematics programs. That is why many of us say: Ban all online mathematics courses!

5. ## Re: Half Angle of Tan

AMEN to that! Thank you!

6. ## Re: Half Angle of Tan Originally Posted by silentwhspr22 AMEN to that! Thank you!
Here are two forms that the program may like!
$\dfrac{5}{{6 + \sqrt {11} }}$ OR $\dfrac{{6 - \sqrt {11} }}{5}$

Please try these and tell us if either works.