Indicating the maximum value

How to indicate the maximum value on the given curve

z1 = [0.00008 0.009]';
a11 = -1:0.001:1;
k1 = atan(((0.01/2 + a11)./z1)) + atan((0.01/2 - a11)./z1);
plot(a11,k1(1,:),'-k',a11,k1(2,:),'-r')

[Matt J]

Duplicate of

https://www.mathworks.com/matlabcentral/answers/1696205-how-to-indicate-the-maximum-value-in-the-plotted-curve-in-matlab?s_tid=srchtitle

Answer 1

[Davide Masiello]

z1 = [0.00008 0.009]';
a11 = -1:0.001:1;
k1 = atan(((0.01/2 + a11)./z1)) + atan((0.01/2 - a11)./z1);
[~,idx_k1] = max(k1,[],2);


plot(a11,k1(1,:),'-k',a11,k1(2,:),'-r',a11(idx_k1(1)),k1(1,idx_k1(1)),'*b',a11(idx_k1(2)),k1(2,idx_k1(2)),'*b')
text(a11(idx_k1(1))+0.05,k1(1,idx_k1(1)),num2str(k1(1,idx_k1(1))))
text(a11(idx_k1(2))+0.05,k1(2,idx_k1(2)),num2str(k1(2,idx_k1(2))))

[Amy Topaz]

Thank you,

Also How to indicate the numerical value at the top of the curve?

[Davide Masiello]

Edited the code, now it does that too.

If correct, please accept the answer for reference to other users with the same problem.

[Sam Chak]

+1.

[Steven Lord]

Another way to plot a marker at the maximum point, assuming you don't want any other markers, is to use the MarkerIndices property of the line.

x = 0:180;
s = sind(x);
[~, location] = max(s);
plot(x, s, 'o-', 'MarkerIndices', location, ...
    'MarkerFaceColor', 'r') % Make the marker stand out in red