Finding the elements of these sets

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Math100
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Homework Statement
Write each of the following sets by listing their elements between braces.
Relevant Equations
None.
Can anyone please check/confirm my answers? I've shown my work and I boxed around all of my answers. Thank you.
 
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  • Handwritten solutions to set-builder problems 6, 8 and 10 on lined paper: 6) {x in R: x^2 = 9} gives x = ±3, boxed as {-3, 3}; 8) {x in R: x^3 + 5x^2 = -6x} factored as x(x+2)(x+3) = 0, boxed as {-3, -2, 0}; 10) {x in R: cos x = 1} gives x = 2πn, boxed as {2πn}.
    Work 1.jpg
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It's good except the last one, where you should specify what values n can take.
 
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FactChecker said:
It's good except the last one, where you should specify what values n can take.
But how should I specify what values n can take? Any hints?
 
Math100 said:
But how should I specify what values n can take? Any hints?
Can n be an arbitrary rational number, such as 1/2? Can n be any real number? Some details on the possible values of n are what @FactChecker is looking for.
 
Just say what set of values n can take. Like {##2\pi n, n \in ?##}
 
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FactChecker said:
Just say what set of values n can take. Like {##2\pi n, n \in ?
{...,-4pi, -2pi, 0, 2pi, 4pi, ...}
 
Math100 said:
{...,-4pi, -2pi, 0, 2pi, 4pi, ...}
So for ##2\pi n## to take on those values, what set of numbers does n belong to? That's what we're trying to get you to tell us.
 
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Mark44 said:
So for ##2\pi n## to take on those values, what set of numbers does n belong to? That's what we're trying to get you to tell us.
{..., -2, -1, 0, 1, 2, ...}
Is that the right answer?
 
Math100 said:
{..., -2, -1, 0, 1, 2, ...}
Is that the right answer?
Also known as the integers, ##\mathbb{Z}##
So a good expression of the answer is {##2\pi n, n \in \mathbb{Z}##}
 
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FactChecker said:
Also known as the integers, ##\mathbb{Z}##
So a good expression of the answer is {##2\pi n, n \in \mathbb{Z}##}
Thank you so much!
 
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