Question

Complete the definition of the backsub function below by implementing the backward substitution algorithm. This function takes as input:

• U, an n x n upper triangular matrix
• b, an n x 1 vector for the right-hand-side of the matrix equation

and returns as output:

• x, an n x 1 solution vector x

function x = backsub(U,b)

% Initialize the output vector. This will speed up computation by pre-allocating the memory.

n = length(b);

x = zeros(size(b));

% Do the backward substitution below. It should work for any size uppertriangular matrix [U].

x(n) = b(n)/U(n,n);

for i = n-1:-1:1

end

end

U = [1 2;0 2];

b = [2;1];

x = backsub(U,b)

Answer 1

`Hey,

Note: Brother in case of any queries, just comment in box I would be very happy to assist all your queries

U = [1 2;0 2];

b = [2;1];

x = backsub(U,b)

function x = backsub(U,b)

% Initialize the output vector. This will speed up computation by pre-allocating the memory.

n = length(b);

x = zeros(size(b));

% Do the backward substitution below. It should work for any size uppertriangular matrix [U].

x(n) = b(n)/U(n,n);

for i = n:-1:1
x(i) = b(i)/U(i,i);
b(1:i-1)=b(1:i-1)-U(1:i-1,i)*x(i);
end

end

Kindly revert for any queries

Thanks.