I try to solve this equation with secant method in MATLAB.

fn=40*n^1.5-875*n+35000

my initial guess is n1=60; n2=68; I want to find root and absolute relative approximate

error at the end of each iteration. Can you help me repair my file?

This is my m-file:

Code:

clc
clear
n1=60;
n2=68;
tol=1e-3;
err0=3;
iter=0;
fprintf('iteration n relative approximate error\n')
while err0>=tol
iter=iter+1;
fn1=40*(n1).^1.5-875*(n1)+35000;
fn2=40*(n2).^1.5-875*(n2)+35000;
nnew=n2-fn2*((n2-n1)/(fn2-fn1));
fnnew=40*(nnew).^1.5-875*(nnew)+35000;
err(iter)=(abs((nnew-n2)/nnew))*100;
fprintf('%2d %f %f\n',iter,nnew,err(iter))
if nnew>n1
n1=nnew;
else
n2=nnew;
end
end
nnew
iter