- #1
Sam_
- 15
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For n a nonnegative integer, what (in terms of n) is the sum of the n-th powers of the roots of the polynomial x^6 - 1 ?
O1O said:The only roots of
x^6 - 1 = 0
are +1, and -1.
O1O said:Sorry, of course there are; I foolishly put the others down to "complex" roots. Hmm.
The 6 [real] roots are:
x = 1
x = (-1)^(1/3)
x = (-1)^(2/3)
x = -1
x = -(-1)^(1/3)
x = -(-1)^(2/3)
That's the hard part done.
d_leet said:Still wrong. There are not six real roots. There are two real roots ( 1, and -1) and then 4 complex roots. Do you, and it really should be the OP, know how to find the compex roots of this equation? In other words do you know how to find all the 6th roots of unity(one)?
Gib Z said:I would tend to believe (-1)^(1/3) is not real :( He could have expressed them better yes, but that is still correct.
HallsofIvy said:The "nth roots of unity" are equally spaced around the unit circle. In particular that means the sum of the nth roots of unity themselves add to 0, if n is even, or 1, if n is odd.
The formula for calculating the sum of 6th roots of x^6 - 1 for n is n*(x^6 - 1)^(1/6).
The formula for the sum of 6th roots of x^6 - 1 for n can be derived using the geometric series formula and the properties of roots.
The 6th root is significant because it corresponds to the exponent of x^6 in the expression x^6 - 1. This means that the formula is specifically designed for finding the sum of 6th roots.
Yes, this formula can be used for any value of n as long as the expression x^6 - 1 is defined for that value of n. However, the resulting sum may be a complex number for certain values of n.
This formula can be used to calculate the sum of 6th roots in various mathematical equations, which can have applications in fields such as physics, engineering, and computer science. It can also be used to solve certain types of mathematical problems and make predictions about the behavior of complex systems.