I have hard time with trig
Find the 3 smallest positive x-intercepts of the graph of
y = cos 12x + cos 16x + cos 20x
and list them in increasing order.
+163 Since you are looking for an x intercept you can set y = 0
this looks like trig identities
https://www2.clarku.edu/faculty/djoyce/trig/identities.html should help
