CONJ function
CONJ(A) returns the complex conjugate of a complex number. The complex conjugate of the complex number a + bi is a − bi.
The argument A can be a real number, a complex number or a matrix. When it is a matrix, the function returns a matrix with the same dimensions and with the CONJ function applied to all elements.
Note that
$$ (a+bi)\times (a-bi) = abs(a+bi)^2 $$
Example
CONJ(2+3i) returns 2-3i