Root
Calculate square roots, cube roots, and nth roots
How to use Root
- 1Enter the radicand (the number under the root) and the index, such as 2 for square root.
- 2Choose whether to allow complex results for negative inputs if offered.
- 3Read the principal root and, for squares, the positive and negative values.
Understanding roots
n-th root of x = y where y^n = x; square root means index 2A root answers the question 'which number, raised to this power, gives the radicand'; the square root is the most common case.
Even roots of negative numbers are not real, so calculators either report an error or return a complex number depending on mode.
Frequently asked questions
Why are there two square roots?
Both a positive and a negative number square to the same value; the principal root shown is the non-negative one.
Can I take a root of a negative number?
Odd roots (cube, etc.) of negatives are real, but even roots are not real unless complex mode is on.
What is the index?
It is the small number that says which root; 2 is square root, 3 is cube root, and so on.