Finding the highest and lowest point of a function

Hi i want to ask about something, i want to solve and locate the highest and lowest points of a function using matlab gui but i dont know how to code it. The function is user defined and here is my code:

funcString = get(handles.edit1,'String');

funcHandle = str2func(['@(x)' funcString]);

x = linspace(10,-10,100);

y = funcHandle(x);

plot(handles.axes1,x,y);

please help

[Rik]

What have you tried?

The obvious method of min and max will only work if your linspace happens to actually return the exact correct points, so you will need something smarter. Do you have the curve fitting toolbox? Otherwise you might be stuck with fminsearch.

Answer 1

[Aditya Srikar]

Hi Joe

Let X represent a list of X-coordinates of all points of a curve.

Let Y represent a list of Y-coordinates of all points of a curve.

To obtain maximum value of Y-coordinate

Y1 = max(Y)

To obtain X-coordinate of point with maximum Y-coordinate value

X1 = X(find(Y == Y1))

To obtain minimum value of Y-coordinate

Y2 = min(Y)

To obtain X-coordinate od point with minimum Y-coordinate value

X2 = X(find(Y == Y2))

Hope it helps !