Use the slider to change the value of \(a\).

- What do you notice?
- What questions do you have?

Decide which of the following is the gradient function of \(\sin 3x\) and justify your answer.

- \(\cos 3x\)
- \(3\cos x\)
- \(3\cos 3x\)

It may be useful to use the GeoGebra applet or graph sketching to help you explain.