Find the exact value of $$sin(\frac{3\pi}{8}$$

Trigonometric ratios and functions, the unit circle, inverse trig functions, identities, trig graphs, etc.

Find the exact value of $$sin(\frac{3\pi}{8}$$

Find the exact value of $sin(\frac{3\pi}{8}$

Since $\frac{3\pi}{8} = (\frac{1}{2}) (\frac{3\pi}{4})$, can I use the half angle formula?

$sin(\frac{3\pi}{8}) = \pm \sqrt{ \frac{1-cos(\frac{3\pi}{4})} {2} }$

Do i use the "+" because of $\frac{3\pi}{8}$ being in Q!?
anonmeans

Posts: 45
Joined: Sat Jan 24, 2009 7:18 pm

anonmeans wrote:Find the exact value of $sin(\frac{3\pi}{8}$

Since $\frac{3\pi}{8} = (\frac{1}{2}) (\frac{3\pi}{4})$, can I use the half angle formula?

Yes, that would be the way to go. And yes, use the positive square root!

stapel_eliz

Posts: 1797
Joined: Mon Dec 08, 2008 4:22 pm