How to Calculate the Complex Roots of x^5 = 10?

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SUMMARY

The discussion focuses on calculating the complex roots of the equation x5 = 10. The real root is established as 1.858, while the complex roots can be derived using the polar form of complex numbers. Specifically, the equation can be transformed into z5 = 1, and the solutions can be multiplied by the fifth root of 10. The use of Newton's method is discouraged for finding complex solutions, and instead, the polar representation of 10 should be utilized.

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  • Understanding of complex numbers and their properties
  • Familiarity with polar form representation of complex numbers
  • Knowledge of Argand diagrams
  • Basic calculus concepts, particularly Newton's method
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Homework Statement
Given x^5=10, find the five roots and plot them on an Argand diagram.
Relevant Equations
Newton's method.
Mentor note: Member reminded that some effort must be shown.
Real root is 1.858.
Just don't know which method to use to find the 4 complex roots
 
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x^5=10
(\frac{x}{\sqrt[5]{10}})^5=z^5=1

So get solutions of ##z^5=1## and multiply them with ##\sqrt[5]{10}##.
 
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Newton's method will only find the real solutions. With complex numbers, you should consider the properties of complex numbers to get the other, complex solutions. Even for the real solution, they probably don't want you to use Newton's method, but rather just leave that solution as ##10^{1/5}##.
For the complex solutions, do you know about the representation of a complex number in its polar form (##re^{i\theta}##)? If so, consider 10 in its polar form: ##10e^{i0} = 10e^{i2\pi}= 10e^{i4\pi}= 10e^{i6\pi}= 10e^{i8\pi}= 10e^{i10\pi}##. Now take the fifth root of the individual factors, 10 and ##e^{i2n\pi}##
 
mardybum9182 said:
Just don't know which method to use to find the 4 complex roots

Do you know what an Argand diagram is?
 

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