# What is the complex conjugate of 2sqrt10?

Dec 8, 2015

$2 \sqrt{10}$

#### Explanation:

To find a complex conjugate, simply change the sign of the imaginary part (the part with the $i$). This means that it either goes from positive to negative or from negative to positive.

As a general rule, the complex conjugate of $a + b i$ is $a - b i$.

You present an odd case. In your number, there is no imaginary component. Therefore, $2 \sqrt{10}$, if expressed as a complex number, would be written as $2 \sqrt{10} + 0 i$.

Therefore, the complex conjugate of $2 \sqrt{10} + 0 i$ is $2 \sqrt{10} - 0 i$, which is still equal to $2 \sqrt{10}$.