Explain why the value of the function f(x) = 25 sin pi/50 (x+20) - 55 at x=3 is the same as the value of the f

explain why the value of the function f(x) = 25 sin pi/50 (x+20) - 55 at x=3 is the same as the value of the function at x=7

Due to Calculus. If you derive the function, find the critical values, and test each region, x=3 and x=7 will both be relative extrema. Both either minimums or maximums.

If you haven't learned calculus, you can take a graphing approach and explain it that way. They both have a horizontal line that passes thru both of them. Etc etc. Fun.

I was going to answer this question, but then I took an arrow to the knee...