So I have this XY Scatter graph that contains about 15,000 data points. This graph is sinusoidal and oscillates back and forth about 11 times throughout the graph. What I need to do is to get the values at the peaks and valleys of each oscillation. Since there are so many data points, it's going to take too long to look through the data to find the exact maximum and minimum at each peak and valley. I'm wondering if there's a way I can just like click on the peaks of the graph and have Numbers spit out the value at that point. If not, is there any other way you can think of that would help me accomplish this task more efficiently?