how i can write this in matlab

[Jan]

Do you want some code to evaluatre this expression? Then what is i and j?

Or do you want to write this as a lable or title of a diagram and ask for bold font, italics and the dot?

Answer 1

[Matt Gaidica]

i - 1.3 * diff(y) * j

[Walter Roberson]

Probably not. and are usually used to represent unit vectors.

Answer 2

[Walter Roberson]

That is a bit ambiguous, but most likely the MATLAB for that would be

-1.3j * diff(y)

You might notice that this has no i in it. It is likely that you should not use

i - 1.3j * diff(y)        %PROBABLY WRONG

In the image you show, i and j are most likely unit vectors along two axes (that are usually mapped to x and y) . MATLAB does not have distinct unit vectors in multiple dimensions, just real values and imaginary values . MATLAB uses both i and j to represent the same value, sqrt(-1), so (for example) 1*i - 1*j would be 1*sqrt(-1) - 1*sqrt(-1) which would be 0.

[Adam Danz]

Also, watch out for predefined i and j variables which are common variable names in loops. That can be fixed by including

clear i j

if you're running this in a script.