# Solve an equation through iteration in Matlab

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kasim on 13 Nov 2019
Commented: David Hill on 13 Nov 2019
Hi, I am trying to solve the following 750 = x^4 + x in matlab using iteration
I want Matlab to display the values it obtains for x, I have tried to use a for loop but with no luck.
Would anyone be able to help out with a basic code I would need.
Kind regards

David Hill on 13 Nov 2019
function b = Solution(a,b)%a and b must bound the solution (a=5.2, b=5.3)
f=@(x)x^4+x-750;
while f(b)>.000001%whatever accuracy you want here
if f((a+b)/2)<0%this is a simple half slitting technique
a=(a+b)/2;
else
b=(a+b)/2;
end
end

kasim on 13 Nov 2019
Hi David,
When running the code, I am getting the following error:
Error in untitled2 (line 5)
while f(b)>.000001%whatever accuracy you want here
David Hill on 13 Nov 2019
Works perfectly for me. Did you set it up as a function? If not, you need to assign values to a and b.
a=5.2;
b=5.3;
f=@(x)x^4+x-750;
while f(b)>.000001%whatever accuracy you want here
if f((a+b)/2)<0%this is a simple half slitting technique
a=(a+b)/2;
else
b=(a+b)/2;
end
end