角阵的求解 Ux= b MAtLaB x=zeros(n, 1) X=zeros(n, for k=n: -1 for k=n: -1: 1 x(k)=b(k)/U(k, k) j=k+l:n i=(1k-1)7; x(k)=(b(k)-U(k)*x()/U(kk); b()=b()-X(k)*U(k) end end 求出x(m),然后把x(n)消掉三角阵的求解 Ux = b x = zeros(n, 1); for k = n:-1:1 x(k) = b(k)/U(k,k); i = (1:k-1)’; b(i) = b(i) – x(k)*U(i,k); end x = zeros(n, 1); for k = n:-1:1 j = k+1:n x(k) = (b(k) – U(k,j)*x(j))/U(k,k); end 求出x(n)，然后把x(n)消掉 = = n j i ij j bi u x