Question

sin 3pi/8 use half angle formula to find exact value. please show work

Answer 1

\[cos(2\theta) = 1-2sin^2\theta\]
So,
\[cos(2 \times\frac{3\pi}{8}) = 1-2sin^2\frac{3\pi}{8}\]Left side is easy to simplify (special angle), then you can find sin(3pi/8)