Write each root using exponents and evaluate. ∜-81
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Recognize that the expression ∜-81 represents the fourth root of -81.
Express the fourth root using exponents: ∜-81 = (-81)^{1/4}.
Note that taking the fourth root of a negative number in the real number system is not possible, as even roots of negative numbers are not real.
Consider the complex number system, where the fourth root of a negative number can be found.
Express -81 as a complex number: -81 = 81 * (-1), and use the property that (-1)^{1/4} can be expressed in terms of complex numbers.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Roots and Exponents
Roots are the inverse operations of exponents. The nth root of a number 'a' is a value 'b' such that b^n = a. For example, the square root of 9 is 3 because 3^2 = 9. In this case, the fourth root (∜) indicates we are looking for a number that, when raised to the fourth power, equals -81.
When dealing with even roots, such as the square root or fourth root, the result is typically defined only for non-negative numbers in the real number system. This means that the fourth root of -81 does not yield a real number, as no real number raised to an even power can produce a negative result. Instead, we must consider complex numbers to find a solution.
Complex numbers extend the real number system to include solutions to equations that do not have real solutions. A complex number is expressed in the form a + bi, where 'a' is the real part and 'bi' is the imaginary part. For the fourth root of -81, we can express it in terms of complex numbers, leading to solutions involving the imaginary unit 'i', where i^2 = -1.