Imaginary numbers allow us to represent the square root of a negative number or the product of a real number and the imaginary unit, j. The square root of a negative number is called a pure imaginary number. The symbol represents the principal square root of a and is never negative.
If a is a real number, then is a pure imaginary number and
The form a+bj is known as the rectangular form of a complex number, where a is the real part and b is the imaginary part.
Two complex numbers are equal if both the real parts are equal and the imaginary parts are equal.
Given a+bj and c+dj are two complex numbers. Then, a+bj = c+dj if and only if a=c and b=d.
Example 2 Solve 4+3j = (x+2) + 7j + yj
Real parts are equal
Imaginary parts are equal