how to find two minimums within a range?

Hello People,

I got stuck on question regarding finding 2 minima of function. the equation is

f(x)= exp(-sqrt(x))+ 0.1*sin(3x)

In question it says using function handles, does that mean i have to define function handle specifically, and call it later or i can use anonymous function. I have written following code using anonymous function but it won't return both values together.

>>fminbnd(@(x)exp(-sqrt(x))+0.1*sin(3*x),0,2) and

>>fminbnd(@(x)exp(-sqrt(x))+0.1*sin(3*x),2,5)

Any suggestions would help. As always,thank you for your trouble and Good health to you.

Answer 1

[Bladi Toaza]

As I understand you are looking fot the local minima of the functions. You can use the function islocalmin. This will return a logical array with values 1 (true) when it is a lcoal minima.

f= exp(-sqrt(x))+ 0.1*sin(3x)

TF = islocalmin(f)

plot(x,f,x(TF),f(TF),'r*')

This will return the local mimima of the functions (that could be 1,2 or more).