What is wrong with my code?

I've included a picture of my prompt. This is what I have so far and I don't understand why it doesn't work. Any tips or guidance is appreciated!

n=1;
while (pi_val<=.000000001)
    syms n
    pi_val=sqrt(6*symsum(1/n^2, n, 1, Inf))
end

Answer 1

[Siyu Guo]

You try to read the variable "pi_val" before you have initialized it by a write operation. This is an error, at least for MATLAB 2012 or lower. Besides, I cannot see any reason for the use of this loop.