Answer
$15, \ 36^\circ$.
See the graph below.
Work Step by Step
For the equation
$$
y=15\cos 10x
$$
the amplitude is $15$ and the period is $P=\frac{360}{10}=36^\circ$.
See the graph below.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.