Mark the peak of a graph

I'm trying to place a marker at the peak power value of a graph but I'm having trouble. This is my code,

[Peak, PeakIdx] = findpeaks(Power);

plot (Resistance,Power)

hold on

grid on

ylabel ('Power (mW)')

xlabel ('Resistance (\Omega)')

title ('Power vs Resistance')

text(Resistance(PeakIdx), Peak, sprintf('Peak = %6.3f (mW)', Peak))

I get "Peak=24.900 (mW)" but I'd like there to be some sort of marker at the exact location of the peak on the graph. I've looked around and found a page that should be answering my question but I must be doing something wrong. On the image below I would like there to be a circle (or something) to more clearly indicate that peak power occurred at 1000 ohms. I can put a couple spaces in to move "Peak..." over (' Peak = %6.3f (mW)', Peak). Any suggestions? Thanks in advance.

Answer 1

[KSSV]

[Peak, PeakIdx] = findpeaks(Power,Resistance);
findpeaks(power,Resistance)  
hold on  
grid on  
ylabel ('Power (mW)')  
xlabel ('Resistance (\Omega)')  
title ('Power vs Resistance')  
text(Resistance(PeakIdx), Peak, sprintf('Peak = %6.3f (mW)', Peak))

[Brian Hoblin]

This comes really close but my "text..." line causes "Index exceeds matrix dimensions". Any idea on how to correct that?

[Brian Hoblin]

Ok. I messed around with both suggestions and I was able to get 2 different versions that both satisfy. Sorry I couldn't accept both because both were very helpful. One utilizes a legend and the one I needed to add a 'hold on' to. Thank you for your assistance.