Question 1007085: Is the product if 2 complex conjugates always a real number? Explain by using a specific example, and a general example (x's and y's). Answer by ikleyn(52790) (Show Source):
1) Is the product of 2 complex conjugates always a real number?
Yes, it is.
2) Explain by using a specific example
Specific example:
Let z = 3 + 4i.
Then = 3 - 4i.
(3+4i)*(3-4i) = = = 9 - 16*(-1) = 9 + 16 = 25.
3) Explain by using a general example (x's and y's):
Let z = x + yi.
Then = x - yi.
(x+yi)*(x-yi) = = = = .