When do I need point operator when using power function?

I want to know ,how can I know when is the point(dot) use in power,when I want to calculate something.

In matrix calculation is always need the . ?

You how to decide use or not use the point

a.^4 a^4

Answer 1

[Zack Peters]

The '.' syntax is used to denote element-wise multiplication. What this means is that each element of variable 'a' will be raised to the power of 4 rather than have the entire variable 'a' raised to the power of 4.

If 'a' were to be a single value then it doesn't make any difference. However, if 'a' were a matrix then you can begin to see the difference in output of the element-wise operator

~Zack

[Mohammed Hamdalla]

thank you man that really helped.

[Steven Lord]

As a concrete example:

A = [1 2; 3 4]

A = 2×2

1 2 3 4

B = A.*A % Multiply each element of A by itself, element-wise

B = 2×2

1 4 9 16

B2 = A.^2 % Same as B

B2 = 2×2

1 4 9 16

C = A*A % Perform matrix multiplication

C = 2×2

7 10 15 22

C2 = A^2 % Same as C

C2 = 2×2

7 10 15 22

% Elements of C are the dot product of the corresponding rows and columns of A
C(1, 2) == dot(A(1, :), A(:, 2)) % true

ans = logical
   1