# how to run operation row by row. Ex row(n) divide row(n+1)

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Noriham B on 2 Mar 2023
Commented: DUY Nguyen on 2 Mar 2023
clc
clear
syms f(x)
f(x) = exp(-((x).^2));
a =0; % lower limit
b = 1; %upper limit
for j=1:6
n = 2.^j;
h = (b-a)/n;
kamir = vpa(int(f,x,a,b));
s = 0.5*(f(a)+f(b));
for i=1:n-1
s = s+f(a+i*h);
end
I =vpa(h*s);
fprintf(' \t %6d \t %f.4 \n ',n,I)
end
Above is my code. after run, we will get 2 column...
for the second column...what I want to do is...I want to compute row(n)/row(n+1)
Hopefully dear all professor/Dr/expert can help me with this problem..thank you in advance

DUY Nguyen on 2 Mar 2023
Hi, in this modified code, I added a prev_I variable to store the previous value of I. After computing I, we compute the ratio as I / prev_I and print it in the third column!
clear
syms f(x)
prev_I=1;
f(x) = exp(-((x).^2));
a =0; % lower limit
b = 1; %upper limit
fprintf('n\t\tIntegral\tRatio\n');
n Integral Ratio
for j= 1:6
n = 2.^j;
h = (b-a)/n;
kamir = vpa(int(f,x,a,b));
s = 0.5*(f(a)+f(b));
for i=1:n-1
s = s+f(a+i*h);
end
I =vpa(h*s);
if i==1
ratio =1;
else
ratio = I / prev_I;
end
fprintf('%d\t\t%.4f\t\t%.4f\n', n, I, ratio)
prev_I = I;
end
2 0.7314 1.0000 4 0.7430 1.0159 8 0.7459 1.0039 16 0.7466 1.0010 32 0.7468 1.0002 64 0.7468 1.0001
##### 3 CommentsShow 1 older commentHide 1 older comment
Noriham B on 2 Mar 2023
its working actually..juz that
should be
else
ratio = prev_I/I ;
the rest is ok...tq so much sir for helping me...
now its working..may God bless u
DUY Nguyen on 2 Mar 2023
Oh, yes! I see.
No problem :)

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