Question 1

What is the value of i^2, where i is the imaginary unit?

Accepted Answer

-1 — The imaginary unit i is defined by i^2 = -1.

Question 2

For the complex number z = 5 - 2i, what is the imaginary part, Im(z)?

Accepted Answer

-2 — In z = a + bi, b is the imaginary part. Here a = 5 and b = -2, so Im(z) = -2.

Question 3

Simplify (3 + 2i) + (1 - 5i). Give your answer in the form a + bi.

Accepted Answer

4 - 3i — Add real parts: 3 + 1 = 4. Add imaginary parts: 2 + (-5) = -3. So the answer is 4 - 3i.

Complex Numbers

Sample practice questions