# I am facing problem with big fraction

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Muhammad Usman on 6 Oct 2019
Commented: Walter Roberson on 6 Oct 2019
Hello everyone,
When i am writing the following code, "sumx" returns me value in fraction, i want to show my result in terms of "pi". Need some help
n=3;
k=1;
for S=1:n
if k==n
sumx=pi/2;
else
sumx = pi/2+(2/pi)*((((-1).^k(1,:))-1).*cos(k(1,:)*x)./(k(1,:).^2));
plot(x,sumx,'r-')
end
end

#### 1 Comment

Walter Roberson on 6 Oct 2019
What do you expect your values to look like? Are you expecting a vector something like
(35184372088832*pi^2 - 219978174876521)/(70368744177664*pi),
(281474976710656*pi^2 - 1766249117313443)/(562949953421312*pi)
Did you notice that your k does not change in the loop, and so k==n is either always true (if n happens to be 1, which it is not) or else always false (if n happens to be different from 1, which is the case.)
Did you notice that your statements in the loop do not depend upon S?
Did you notice that "plot on" is not set so you are plotting the same thing every time?
Did you notice that k is a scalar, but you are indexing it as if it were a row vector or 2D array ?