Q
QuestionMathematics

What is an important difference between the square root and cube root of a negative number? Discuss and provide examples.
6 months agoReport content

Answer

Full Solution Locked

Sign in to view the complete step-by-step solution and unlock all study resources.

Step 1
: Understand the concept of square roots and cube roots.

A square root of a number is a value that, when multiplied by itself, gives the original number. For example, the square root of 9 is 3 because 3 * 3 = 9. However, not all numbers have real square roots. Negative numbers do not have real square roots because multiplying any real number by itself will always result in a non-negative value. A cube root of a number is a value that, when cubed (multiplied by itself twice), gives the original number. For example, the cube root of 27 is 3 because 3 * 3 * 3 = 27. Unlike square roots, cube roots of real numbers can be either positive or negative.

Step 2
: Examine the properties of square roots and cube roots of negative numbers.

The square root of a negative number is not a real number. Instead, we use the imaginary unit, i, defined as the square root of - 1. So, for example, the square root of - 9 is 3i because (3i) * (3i) = (- 3) * (- 3) = 9. On the other hand, the cube root of a negative number is a real number. This is because multiplying any real number by itself twice and then by - 1 will result in a real number. For example, the cube root of - 27 is - 3 because (- 3) * (- 3) * (- 3) * (- 1) = 27.

Final Answer

The essential difference between the square root and cube root of a negative number is that the square root of a negative number results in an imaginary number, while the cube root of a negative number is a real number. Imaginary numbers are required to represent square roots of negative numbers, whereas cube roots of negative numbers are real and have real solutions.