<s>[INST] Convert the given set into roster notation: Problems:
Find $A$, where
1) $A = \{x \in \mathbb{R} \mid x^4 - 1 = 0\}$
2) $A = \{x \in \mathbb{C} \mid x^4 - 1 = 0\}$
Attempt: 
Solving the equation:
$x^4 - 1 = (x^2)^2 - 1^2 $
$= (x^2 - 1)(x^2 + 1) $
$= (x-1)(x+1)(x^2 + 1) $
$= (x - 1)(x + 1)(x^2 - i^2) $
$= (x-1)(x+1)(x-i)(x+i) $
1) Since $x$ is defined as a real number in this case, $A= \{1,-1\}$.
2) Since $x$ is defined as a complex number in this case, $A= \{1,-1, i, -i\}$.
Is my work correct?
 [/INST] Yes, your answer and notation are correct.
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