What type of index represents roots and is formulated as a^(1/n) = n√a?

The correct answer is indeed Fractional Index. This type of index, also known as a rational exponent, involves an exponent that is represented as a fraction. The expression a^(1/n) can be interpreted as the nth root of a, which aligns perfectly with the definition of a fractional index.

In mathematical terms, when you raise a number to a fractional exponent, the numerator indicates the power, while the denominator specifies the root. For example, if n is 2, then a^(1/2) represents the square root of a. This formulation highlights the relationship between exponents and roots in mathematics, confirming that fractional indices signify these operations effectively.

The other answer choices represent different concepts. Whole Number Index pertains solely to positive integers as exponents, while Negative Index refers to exponents that are negative, indicating the reciprocal of the base raised to the absolute value of the exponent. Logarithmic Index relates to logarithmic functions, which are fundamentally distinct from fractional indices. Thus, among the provided options, Fractional Index is the one that accurately represents the formulation a^(1/n) = n√a.