Generally speaking, algebraic expressions with the shape √a are called quadratic roots, where a is called root. When a≥0, √a represents the arithmetic square root of a; When a is less than 0, the value of √a is a pure imaginary number (in the root formula of a quadratic equation with one variable, if it is negative under the root sign, the equation has two * * * yoke imaginary roots).

The main method to judge whether a quadratic root is the simplest quadratic root is according to the definition of the simplest quadratic root, or intuitively observing that the index of each factor (or factor) of the root number is less than the root index 2, and the root number does not contain the denominator. When the root number is polynomial, factorization should be carried out first, and then observation should be carried out.

Simplest quadratic radical

The simplest quadratic radical condition:

1, the factor of the root sign is an integer or letter, and the factor is an algebraic expression;

2. The root sign does not contain a factor or a factor that can be converted into a square number or a flat way.

Refer to the above information: Baidu Encyclopedia-Secondary Radical