In this lesson, we will learn new vocabulary related to the general algebraic concepts of roots and exponents.
- imaginary number
- i
- complex number
- radical
- rational exponent
- exponential
- logarithm
Imaginary and Complex Numbers
An imaginary number is a number that is mathematically useful but impossible. √-1 (also written i) is an imaginary number. This number is imaginary because the product of two numbers should be positive, not negative. √-16 is an imaginary number that can be rewritten as 4i.
A complex number has both real and imaginary parts. It’s usually written a + bi. The a represents the real number, and the bi represents the imaginary number, like this: 2 + 3i. In this expression, 2 is a real number and 3i (or √-9) is the imaginary number.
Rational Exponents and Exponentials
Roots (also called radicals) are normally written like this:
| √9 | The square root of nine |
| ∛8 | The cube root of eight OR The third root eight |
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