mult. imaginary numbers

5 - 2i
3 + 8i

for this problem i would like to know if i should mult. both the tope and the bottom by
3 + 8i.

also i already know that (i) to the second power is equal to -1. but how would you work it out?

Quote:

---

Originally Posted by allsmiles

5 - 2i
3 + 8i

for this problem i would like to know if i should mult. both the tope and the bottom by
3 + 8i.

also i already know that (i) to the second power is equal to -1. but how would you work it out?

---

multiply numerator and denominator by the conjugate of the denominator ... (3 - 8i)

Quote:

---

Originally Posted by allsmiles

5 - 2i
3 + 8i

for this problem i would like to know if i should mult. both the tope and the bottom by
3 + 8i.

also i already know that (i) to the second power is equal to -1. but how would you work it out?

---

$\displaystyle \frac{5-2i}{3+8i} . \frac{3-8i}{3-8i}$