Complex Numbers and Quadratic Equations – Notes

Introduction to Complex Numbers

A number whose square is negative is called an imaginary number.

A number of the form a + ib, where a and b are real numbers, is called a complex number and is represented by Z.

In the complex number z = a + ib,

• a: Real part of the complex number, denoted by Re z
• b: imaginary part of the complex number, denoted by Im z

If the imaginary part of a complex number is zero, then the number is called a purely real number.

If the real part of a complex number is zero, then the number is called a purely imaginary number.