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317 LearnersLast updated on August 5, 2025

The square root of a negative number involves imaginary numbers. The square root of -1/9 can be expressed in terms of the imaginary unit i, where i = √-1. Therefore, the square root of -1/9 is expressed as √(-1/9) = √-1 * √(1/9) = i * 1/3 = i/3. This is a complex number because it involves the imaginary unit i.
The concept of imaginary numbers is essential for understanding the square root of negative numbers. The imaginary unit i satisfies the equation i² = -1. Therefore, the square root of any negative number can be expressed using i.
For -1/9, the square root is i/3. This is a basic representation of complex numbers, which combine real numbers and imaginary numbers.
To express the square root of -1/9, we use the properties of square roots and imaginary numbers:
Step 1: Break it as √(-1) * √(1/9).
Step 2: Simplify using i for √(-1), so it becomes i * 1/3.
Step 3: The result is i/3, which is a complex number.


Imaginary numbers are not just theoretical; they have practical applications. They are used in electrical engineering, signal processing, and quantum mechanics.
For example, alternating current (AC) circuits use imaginary numbers to analyze and design circuits. Understanding the square root of negative numbers is crucial in these fields.
Many students initially struggle with the concept of imaginary numbers, as they do not have a direct physical representation. It's important to realize that imaginary numbers are a mathematical tool used to solve equations that cannot be solved using only real numbers. They are crucial in many advanced mathematical and engineering applications.
When dealing with square roots of negative numbers, students often make mistakes by ignoring the imaginary unit or misapplying rules of square roots. Let’s explore common mistakes and how to avoid them.
What is the result of multiplying i/3 by 3?
The result is i.
Multiplying i/3 by 3 gives (i/3) * 3 = i.
If z = i/3, what is the magnitude of z?
The magnitude is 1/3.
The magnitude of a complex number z = a + bi is given by √(a² + b²). For z = i/3, the magnitude is √(0² + (1/3)²) = √(1/9) = 1/3.
What is (i/3) * (i/3)?
The result is -1/9.
(i/3) * (i/3) = i²/9 = -1/9, since i² = -1.
What happens when you add i/3 to its complex conjugate?
The result is 0.
The complex conjugate of i/3 is -i/3. Adding them gives i/3 + (-i/3) = 0.
What is the real part of 2 + i/3?
The real part is 2.
In the complex number 2 + i/3, the real part is the coefficient of the non-imaginary number, which is 2.

Vikrant is a passionate Mathematics teacher with over 5 years of teaching experience in both conventional and Vedic Maths. His student-focused approach combines clear concepts with motivation and encouragement, helping students build confidence and develo
: He loves to play the quiz with kids through algebra to make kids love it.
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