# Thread: conjugate of complex number

1. ## conjugate of complex number

To find the conjugate of a complex number, we know that if it is of the form a+ib, then the conjugate is a-ib. Now say I have a very huge expression containing complex numbers in numerators and denominators which is very tough to reduce in the form a+ib. I have to find its conjugate. Then if I replace every i by -i in the expression, will this resultant expression be the required conjugate?

2. I don't think this will work in all cases, can you post the equation in question?

3. ## conjugate of a complex number

Originally Posted by pickslides
I don't think this will work in all cases, can you post the equation in question?
I have attached the expression in pdf file.

4. That method will work. If you replace $\displaystyle \lambda$ and $\displaystyle \eta$ by their conjugates (and if all the other symbols k, x, y represent real quantities), then you will get a valid expression for the conjugate of P.

5. Originally Posted by Opalg
That method will work. If you replace $\displaystyle \lambda$ and $\displaystyle \eta$ by their conjugates (and if all the other symbols k, x, y represent real quantities), then you will get a valid expression for the conjugate of P.
Then in what situation the conjugate can not be obtained by merely changing i to -i. An example please.