In 1:num : numerical expression has 5 elements: only the first used

1:num is not a valid numerical expression in many programming languages. It seems like you are trying to create a sequence from 1 to a certain number. To achieve this, you can use the colon operator in some languages like MATLAB or R.

For example, in MATLAB, you can create a sequence from 1 to 5 as follows:

sequence = 1:5;

This will create a vector [1, 2, 3, 4, 5].