how to plot a graph

Hello,

New to matlab here so hopefully I can get a little more help

[Star Strider]

You deleted your original Question, which was to detect the peaks in the vector in my Answer. I solved it for you, and then, since it’s obviously homework, let you run it to see how it worked.

Your original Question didn’t have anything to do with plotting a graph.

Answer 1

[Star Strider]

This works:

V = [1 4 5 3 8 21 9];
dV = diff([V(1) V]);
neg_dV_idx = find(dV<0);
Peaks = V(neg_dV_idx-1)

Peaks =
     5    21

I broke it out into several lines to make it easier to understand. I will leave it to you to figure out how it works!