Use the rules 𝑑 𝑑𝑥cos(𝑥) = − sin(𝑥) and 𝑑 𝑑𝑥cos(𝑓(𝑥)) = −𝑓′(𝑥)sin(𝑓(𝑥)).

mm-u3-t2-s1-d2

Request an applet

Describe what students should see or notice. That's the cue to build — requests are what get built next.