determinant of a matrix A, using det(A) function in MATLAB giving error

Question

Why do I get these errors:

Subscript indices must either be real positive integers or logicals.

and

Index exceeds matrix dimensions.

When trying to use the det(A) function in MATLAB.

Tried with this code:

A = [1 2 3; 1 2 3; 1 2 3]
A =

 1     2     3
 1     2     3
 1     2     3

det(A)

>> det(A)
Index exceeds matrix dimensions.

matrix2 =

  -31    17
  -70   -48

det(matrix2)

Subscript indices must either be real positive integers or logicals.

Answer 1

You have probably called some variable det:

A = [1 2 3; 1 2 3; 1 2 3];det(A)
ans =
     0
B=[-31 17;-70 -48];det(B)
ans =
   2.6780e+03

both work fine. However if I overwrite det:

det = 2;
det(A)
Index exceeds matrix dimensions.
det(B)
Subscript indices must either be real positive integers or logicals. 

det(A) does not work, since there's no second or third element in det. det(B) does not work, since negative indices are never allowed in MATLAB.