# Describe the difference between real and complex roots. What might be the reason for using a complex root to describe a situation?

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- JOHNLv 76 months agoFavorite Answer
An alternating voltage in a circuit might be described by a complex number. And Ohm’s law for the circuit might be written as V = IZ, where I is a complex number representing the current and Z another complex number representing the total capacitative, inductive and ohmic resistance of the circuit. This procedure is useful because alternating voltages and currents have both magnitude and phase (indeed phase (V) = Arg (V) and phase (I) = Arg (I)), and capacitances and inductances, being complex numbers, have their own effects on the phases concerned. Ohmic resistances are represented by real numbers. The interpretation of V and I when they are real is that they are DC. AC theory is much simplified and made succinct by the use complex numbers. Quantum mechanics uses complex numbers extensively.

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- Anonymous6 months ago
The former is a whole number, whereas the latter is a number that goes beyond the decimal point. One reason for using a complex root would be to determine the length of another side of a right triangle, which would require squaring the lengths of two sides you know, adding them up, and then finding the square root of the sum.

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