What inputs have to be scalar and why cannot we raise an exponential within a square root function please?

Excuse my lack of experience what is the problem here, please?

diff(1/2*sqrt(2*pi^exp(-1*x)^2))
Error using  ^ 
Inputs must be a scalar and a square matrix.
To compute elementwise POWER, use POWER (.^) instead.

This is a somewhat mistaken interpretation of some formula, but I lost the academic reference to be honest.

Answer 1

[Stephen23]

You probably need to use the element-wise power, just like the error message tells you:

>> x = 1:4;
>> diff(1/2*sqrt(2*pi.^exp(-1*x).^2))
ans =

    -0.251803  -0.077017  -0.026488

But this depends on what the formula is supposed to do, which you do not tell us. In any case you should learn about the differences between matrix and element-wise operations:

http://www.mathworks.com/help/matlab/matlab_prog/array-vs-matrix-operations.html