Question

l = [0 1 -2 1 1];

d = [2 -2 4 2 2];

r = [-1 1 -1 -2 0];

b = [2 0 -6 1 4];

n = length(d);

x= zeros(n,1);

for i = 2:n

factor = l(i)/d(i-1);

d(i) = d(i) - factor*r(i-1);

b(i) = b(i) - factor*b(i-1);

end

x(n) = b(n)/d(n);

for i = n-1:-1:1

x(i) = b(i)-r(i)*x(i+1) / d(i);

end

x1 = x(1);

x2 = x(2);

x3 = x(3);

x4 = x(4);

fprintf('\nx1 = %f\nx2 = %f\nx3 = %f\nx4 = %f\n',x1,x2,x3,x4);

this is matlab code!

It's a question of getting answers using the Thomas method.

The answer should be x1=1, x2=0, x3=-1, x4=2, x5=1.

Please fix what's wrong.

Answer 1

CODE:-

l = [0 1 -2 1 1];

d = [2 -2 4 2 2];

r = [-1 1 -1 -2 0];

b = [2 0 -6 1 4];

n = length(d);

x= zeros(n,1);

for i = 2:n

factor = l(i)/d(i-1);

d(i) = d(i) - factor*r(i-1);

b(i) = b(i) - factor*b(i-1);

end

x(n) = b(n)/d(n);

for i = n-1:-1:1

x(i) = (b(i)-r(i)*x(i+1)) / d(i);

end

x1 = x(1);

x2 = x(2);

x3 = x(3);

x4 = x(4);
x5 = x(5);
fprintf('\nx1 = %d\nx2 = %d\nx3 = %d\nx4 = %d\nx5 = %d\n',x1,x2,x3,x4,x5)

screenshots of code and result:-

please like if you find it needfull.....