Creating a Matrix by Manipulation

Hi, How do you create a matrix that is identical to another matrix except for one entry? For example, if there is a matrix A=[1 2 ; 3 4], how do you create a matrix B=[1 10 ; 3 4]?

Thank you.

Answer 1

[Joseph Cheng]

you would index the item like

 A(1,2) = 10; %A(1,2) says row 1 column 2 of A should = 10