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127 LearnersLast updated on December 15, 2025

If a number is multiplied by the same number, the result is a square. The inverse of the square is a square root. The square root is used in fields like quantum mechanics and electrical engineering. Here, we will discuss the square root of -13.
The square root is the inverse of the square of a number.
Since -13 is negative, it does not have a real square root.
In the context of complex numbers, the square root of -13 is expressed as √(-13) = √13 × i, where i is the imaginary unit.
The square root of 13 is approximately 3.60555, making √(-13) approximately 3.60555i.
For negative numbers, we cannot use the typical methods like the prime factorization or long division method for finding square roots because these methods apply to real numbers.
Instead, we use the concept of imaginary numbers.
Complex numbers consist of a real part and an imaginary part. The imaginary unit i is defined as √(-1).
Therefore, the square root of any negative number can be represented as a product of a real number and i.
For example, √(-13) = √13 × i.


Complex numbers are used in various scientific and engineering fields.
In electrical engineering, for instance, they are used to represent impedances in AC circuits.
Understanding the square root of negative numbers is crucial in these areas.
To visualize the square root of -13, consider the complex plane, which is a two-dimensional plane where the horizontal axis represents real numbers and the vertical axis represents imaginary numbers.
The point corresponding to √(-13) would be at (0, 3.60555) on this plane.
Students often make mistakes when dealing with square roots of negative numbers.
These include confusing real and imaginary numbers or misapplying the square root operation.
Let's look at some common mistakes and how to avoid them.
Can you help Max find the modulus of the complex number โ(-13)?
The modulus is approximately 3.60555.
The modulus of a complex number a + bi is given by √(a² + b²).
For √(-13), a = 0 and b = √13.
Therefore, the modulus is √(0 + 13) = √13, which is approximately 3.60555.
A circuit has an impedance of โ(-13) ohms. What is the magnitude of this impedance?
The magnitude of the impedance is approximately 3.60555 ohms.
The magnitude of a complex impedance is the modulus of the complex number.
For √(-13), the modulus is √13, which is approximately 3.60555 ohms.
Calculate the product of โ(-13) and 2i.
The product is -7.2111.
The first step is calculating the product of √13 × i and 2i, which is 2i√13 × i = 2(-1)√13 = -2√13.
The result is approximately -7.2111.
What will be the square root of (-13)ยฒ?
The square root is 13.
(-13)² = 169.
The square root of 169 is 13, since 169 is a positive number.
Find the real part of the complex number 5 + โ(-13).
The real part is 5.
In the complex number 5 + √(-13), the real part is the component without the imaginary unit i.
Therefore, the real part is 5.

Jaskaran Singh Saluja is a math wizard with nearly three years of experience as a math teacher. His expertise is in algebra, so he can make algebra classes interesting by turning tricky equations into simple puzzles.
: He loves to play the quiz with kids through algebra to make kids love it.






