Can someone explain me, what is a real root?

1 Answer
George C.
Oct 22, 2017

A real root is a solution to an equation which is also a real number.

Explanation:

Given an equation in a single variable, a root is a value that can be substituted for the variable in order that the equation holds. In other words it is a "solution" of the equation.

It is called a real root if it is also a real number.

For example:

#x^2-2 = 0#

has two real roots:

#sqrt(2) ~~ 1.414#

#-sqrt(2) ~~ -1.414#

On the other hand:

#x^2+2 = 0#

has no real roots, since #x^2>=0# for any real number #x#.

It does have roots, but they are non-real complex numbers, specifically #sqrt(2)i# and #-sqrt(2)i#.

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