Question

Question 6

Answer 1

Answer:

add, subtract, multiply and divide complex numbers much as we would expect. We add and subtract

complex numbers by adding their real and imaginary parts:-

(a + bi)+(c + di)=(a + c)+(b + d)i,

(a + bi) − (c + di)=(a − c)+(b − d)i.

We can multiply complex numbers by expanding the brackets in the usual fashion and using i

2 = −1,

(a + bi) (c + di) = ac + bci + adi + bdi2 = (ac − bd)+(ad + bc)i,

and to divide complex numbers we note firstly that (c + di) (c − di) = c2 + d2 is real. So

a + bi

c + di = a + bi

c + di ×

c − di

c − di =

µac + bd

c2 + d2

¶

+

µbc − ad

c2 + d2

¶

i.

The number c−di which we just used, as relating to c+di, has a spec