top of page
What are complex numbers?
Complex numbers are a combination of real numbers and imaginary numbers. And by "combination," we mean they can be added together, subtracted, multiplied, divided, put to the power of, etcetera. These combinations of numbers can also be looked at as polynomials.
For example, to multiply two binomials together, we use 'FOIL' (First, Outside, Inside, Last). Multiplying binomials where one term is a real number and one term is an imaginary number isn't any different.
Example:
(2x+iy)^2
(2x+iy)(2x+iy)
4x^2+2ixy+2ixy+iy^2
4x^2+4ixy+iy^2
Using FOIL for multiplying binomials made up of complex numbers. [source]
"i" can also be used for solving problems with variables.
Example:
a^2 = -64i
-8^2 = -64i
a = -8
bottom of page