Given : f : C → C and f(x + iy) = x – iy
where C is set of complex numbers.
Let x1 + iy1 and x2 + iy2 ∈ C thus.
f(x1 + iy1) = f (x2 + iy2)
⇒ x1 – iy1 = x2 – iy2
So, f is one-one function.
Range of f = {x – iy : x + iy ∈ C} = C (co-domain)
f is onto function.
Hence, f is one-one, onto function.
Hence Proved.