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conj

Complex conjugate of symbolic input

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Syntax

conj(x)

Description

conj(x) returns the complex conjugate of x. Because symbolic scalar variables are complex by default, unresolved calls, such as conj(x), can appear in the output of norm, mtimes, and other functions. For details, see Use Assumptions on Symbolic Variables.

For complex x, conj(x) = real(x) - i*imag(x).

example

Examples

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Compute the conjugate of numeric input.

conj(1+3i)
ans =
   1.0000 - 3.0000i

Compute the conjugate of symbolic input.

syms x
f = x^2;
fConj = conj(f)
fConj =
conj(x)^2

Convert symbolic output to double by substituting for x with a number by using subs, and then using double.

fConj = subs(fConj,x,1+2i);        % x is 1+2i
fConj = double(fConj)
fConj =
  -3.0000 - 4.0000i

If the input is real, conj returns the input instead of an unresolved call. Assume x is real and find its conjugate. conj returns x instead of conj(x), as expected.

syms x
assume(x,'real')
conj(x)
ans =
x

Clear the assumption for further computations.

assume(x,'clear')

Input Arguments

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Input, specified as a number, vector, matrix, or array, or a symbolic number, scalar variable, matrix variable, array, function, matrix function, or expression.

Version History

Introduced before R2006a

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See Also

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