standard_description: Understand radian measure of an angle as the length of the arc on the unit circle subtended by the angle.
problem_activity: Problem 1
Find
$${\mathrm{sin}(u-v)}$$
given
$${\mathrm{sin}(u)={8\over17}}$$
with
$${0\leq u \leq {\pi\over2}}$$
and
$${\mathrm{cos}(v)=-{24\over25}}$$
with
$${\pi \leq v \leq {3\pi\over2}}$$
.
Problem 2
Evaluate:
$${\mathrm{sin}(-15^{\circ})}$$
$${\mathrm{cos}(15^{\circ})}$$


aligns: no