Quote by thomas49th
Ahh yes i can see i made a istake in the numerator however I dont see how the denominator can be a²  1?:
(ai)(a+i)
= a² + ai  ai  i²
= a² 1
Does i x i always = 1 regardless of what the sign before it is?
Thanks :)

No … (ai)(a+i)
= a² + ai  ai  i²
= a² + 1.
i x i always =
1 regardless of what the sign before it is!