Some trig questions part 2

• Apr 27th 2009, 08:27 PM
donnyB
Some trig questions part 2

4) sin-1 (square root of 5 over 3)
5) cot pie over 12
6) sint= 1/4. 0<t< pie over 2 and sin t is given.
• Apr 27th 2009, 09:53 PM
SengNee
Quote:

Originally Posted by donnyB

4) sin-1 (square root of 5 over 3)
5) cot pie over 12
6) sint= 1/4. 0<t< pie over 2 and sin t is given.

4) sin-1 (square root of 5 over 3)

Do you mean $\sin^{-1}(\frac{\surd5}{3})$

5) cot pie over 12

You should find $\tan\frac{\pi}{12}$ 1st, then find its reciprocal.
You can you your scientific calculator
or
$\tan\frac{\pi}{6} =\frac{2\tan\frac{\pi}{12}}{1-\tan\frac{\pi}{12}}$ where $\frac{\pi}{6}$ is a special angle.

6) sint= 1/4. 0<t< pie over 2 and sin t is given.

That means it is in the 1st quadrant.