finding the minimum value of a function and corresponding x_min

now after running this code we got plot like parabola by figure anyone can find what is the minimum value of phi1 and at which x it is minimum can any one suggest me how to find the minimum phi1 and what is x_min by code not by figure.so far i am using this code but by this i get incorrect value of x_min that's why i also get wrong min_phi1,x_min should be L/2 and this can be verified by the plot code is attached with question

Answer 1

[KSSV]

doc min.

[val,idx] = min(phi1) ;   % get minimum value of phi1 and it's index 
x_min = x(idx)     % x at which phi1 is minimum 
phi1_min = val    % minimum phi1

[NILESH PANDEY]

Thank You Sir for help i have asked one more question yesterday as : i have to find the value of y(i) till y(i)-y(i-1)<=2.59e-4 can anyone help me with the code first correcting the error then how can i again start the iteration if y(i)-y(i-1)=>2.59e-4 necessary file is attached with question can you help me with the same

[KSSV]

This code shows error...rectify it..