What is the meaning of sum(1:2:9,1:2) in MATLAB?

The expression sum(1:2:9,1:2) in MATLAB is invalid syntax and will result in a syntax error.

The sum function in MATLAB is used to calculate the sum of a set of numbers. The syntax for the sum function is:

sum(x)

where x is a vector or matrix of numbers.

The expression 1:2:9 generates a vector of numbers starting at 1, incrementing by 2, and stopping at 9. The expression 1:2 generates a vector of numbers starting at 1, incrementing by 1, and stopping at 2.

However, when you pass multiple arguments to the sum function, it will attempt to concatenate them into a single matrix or vector. In this case, since the two arguments have different sizes, the concatenation will fail and result in a syntax error.