### Home > PC3 > Chapter 4 > Lesson 4.1.2 > Problem 4-28

4-28.

In parts (a) and (b) below, calculate the product for each pair of complex numbers whose imaginary parts have opposite signs. Pairs of complex numbers such as these are called **complex conjugates**. Use any patterns you discover to answer parts (c) through (e).

,

, Your answers to parts (a) and (b) should be strictly real numbers.

What complex number can you multiply

by to get a real number? What is the complex conjugate of

?What happens when you multiply any complex number by its conjugate?