plot(X1,Y1,...,Xn,Yn) plots each vector Yn versus vector Xn on the same axes.
Accessing Multiple Elements
For the 4-by-4 matrix A shown below, it is possible to compute the sum of the elements in the fourth column of A by typing
A = magic(4);
A(1,4) + A(2,4) + A(3,4) + A(4,4)
You can reduce the size of this expression using the colon operator. Subscript expressions involving colons refer to portions of a matrix. The expression
A(1:m, n)
refers to the elements in rows 1 through m of column n of matrix A. Using this notation, you can compute the sum of the fourth column of A more succinctly:
sum(A(1:4, 4))
Thus, the syntax you are using is to extract columns from your array and use them as the X and Y for plotting purposes.
