Mathematics Grade 12 15 min

Powers of i

Powers of i

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1

Introduction & Learning Objectives

Learning Objectives Define the imaginary unit, i, and state its fundamental property. Calculate the first four powers of i (i^1, i^2, i^3, i^4) and identify their cyclical pattern. Develop and apply a systematic method using division to evaluate i^n for any positive integer n. Evaluate i^n for any negative integer n by applying the rules of negative exponents. Simplify complex expressions involving sums, differences, and products of various powers of i. Recognize and avoid common errors in calculating powers of i, particularly with remainders and negative exponents. What happens when you keep multiplying the square root of -1 by itself? The answer reveals a surprisingly simple and elegant pattern! 🌀 This tutorial explores the powers of the imaginary unit, i. You will disco...
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Key Concepts & Vocabulary

TermDefinitionExample Imaginary Unit (i)The fundamental unit of imaginary numbers, defined as the principal square root of negative one.i = \sqrt{-1}, which means i^2 = -1. Complex NumberA number that can be expressed in the form a + bi, where a and b are real numbers and i is the imaginary unit.3 + 2i is a complex number where a=3 (the real part) and b=2 (the imaginary part). Cyclical PatternA sequence of values that repeats in a predictable, fixed order.The powers of i follow a cycle of four values: i, -1, -i, 1. ExponentA quantity representing the power to which a given number or expression (the base) is to be raised.In i^37, the base is i and the exponent is 37. RemainderThe amount 'left over' after performing a division. In the context of powers of i, we are interested in t...
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Core Formulas

The Fundamental Cycle of i i^1 = i \\ i^2 = -1 \\ i^3 = -i \\ i^4 = 1 These are the four foundational values that form the repeating pattern. Every other integer power of i will simplify to one of these four results. The General Rule for Positive Powers i^n = i^r, where r is the remainder of n \div 4. To find the value of i raised to any positive integer 'n', divide 'n' by 4 and find the remainder 'r'. The value of i^n will be the same as i^r. If the remainder is 0, use r=4, as i^4 = 1. The Rule for Negative Powers i^{-n} = \frac{1}{i^n} To evaluate i raised to a negative exponent, first rewrite it as its reciprocal with a positive exponent. Then, simplify the denominator using the general rule and rationalize if necessary.

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Sample Practice Questions

Easy
According to the fundamental definition of the imaginary unit, what is the value of i^2?
A.1
B.-1
C.i
D.-i
Easy
What is the value of i^3?
A.1
B.-1
C.i
D.-i
Easy
The powers of i (i^1, i^2, i^3, i^4, ...) repeat in a predictable cycle. How many unique values are in this cycle before it repeats?
A.2
B.4
C.8
D.The pattern never repeats

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