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conj

Complex conjugate of symbolic input

Syntax

Description

example

conj(x) returns the complex conjugate of x. Because symbolic 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).

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, variable, array, function, or expression.

See Also

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Introduced before R2006a