Exercises on Complex Numbers - a Summary

In what quadrant does -3i + 4 lie?

• I

• II

• III

• IV

What is the additive inverse of 2 - 4i?

• -2 - 4i

• -2 + 4i

• 2 - 4i

• 2 + 4i

Which statement is NOT TRUE?

• The conjugate of an imaginary number is equal to its additive inverse.

• The additive inverse of an imaginary number is imaginary.

• The conjugate of a complex number is diametrically opposite to it.

• The additive inverse of a complex number has the same magnitude as the original number.

Which is the argument for the polar form of -1 + i?

• 45^o

• 135^o

• 225^o

• 315^o

The modulus of z = -1 + i is...

• 0

• 1

• √2

• 2

What is the product of (2 - 2i) and (3 + 3i)?

• 6

• 12

• -6

• -12

• none of these

When (3 - 4i) is divided by -5i, the quotient is...

• cis 36.9^o

• - cis (-53.1^o)

• cis 143.1^o

• - cis 126.9^o

What is the product of (2 cis 40^o) and (5 cis 140^o)?

• 10 cis 100^o

• -10 cis 180^o

• 10

• -10

Which is NOT a cube root of 27i?

• 3 cis 30^o

• 3 cis 120^o

• 3 cis 150^o

• 3 cis 270^o

How many real 5th roots does 32i have?

• 5

• 3

• 1

• 0