Drawing a periodic function

This code takes two input functions with their periods from the user and plot them. i was asking if i got the total function for the two which is(y)...how can i plot 3 cycles of (y) assuming that it's a periodic function?

[Karan Gill]

Why are you declaring "t" to be symbolic and then giving it a numeric value? Also, you need to look up the theory for how to calculate the period when combining two functions.