Did you read the documentation already? The code is very basic, so reading the "Getting Started" chapters is recommended. The forum cannot replace this.
is the same as:
The square brackets are the concatenation operator, but 2:0.1:7 is a vector already: It is the row vector starting at 2 and going in steps of 0.1 until 7.
From the inside to the outside:
This replies the maximum value of the vector AB along the 2nd dimension. Because AB is a row vector, you can omit the dim and write:
is useless: Amax is the maximum value of m, but while m is a scalar, Amax will equal m. Bmax is the index of the largest element, and for a scalar input you get 1 in every case.
Perhaps this is meant:
[maxValue, maxIndex] = max(AB)
Note: If you proceed to post strange and very basic code in the forum and ask for the details instead of reading the documentation, the forum will loose the interest in solving your problems.