MATLAB: While loop will not stop running

while loop

I have this code to develop the partial sum of (1/k^2). However, when I run the code, the while loop does not stop. Any help with this problem?
function [sum1,error,steps] = psum(tol)
k=1;
sum1=1/(k).^2;
answer=(pi.^2)/6;  
error=abs(answer-sum1);
while error>tol 
    k=1/(k+1)^2;
    term=sum1+(1/(k).^2);
    sum1=sum1+term
    error=abs(answer-sum1)
end
steps=k

Best Answer

You are corrupting the value of k and not doing the term summing properly. These lines:
    k=1/(k+1)^2;
    term=sum1+(1/(k).^2);
should be this instead:
    k = k + 1;
    term=(1/(k).^2);
SIDE NOTE: "error" is the name of an intrinsic MATLAB function, so it would be best to use a different name for your variable (e.g., err).
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