Abstract Algebra[zero polynomial of infinite field]

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In an infinite field F, if a polynomial f(x) in F[x] has an infinite number of roots a, it must be the zero polynomial. This is because if f(a) = 0, then (x - a) divides f(x), indicating that f(x) can be factored by an infinite number of linear factors. However, a non-zero polynomial can only have a finite number of roots, leading to the conclusion that f(x) cannot be non-zero. Therefore, the only polynomial that can have infinitely many roots in an infinite field is the zero polynomial. This logical deduction confirms that if f has infinite roots, it must indeed be the zero polynomial.
malcmitch20
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What would be the best way to show that if F is an infinite field and f(x) is a polynomial in F[x] and f(a)=0 for an infinite number of elements a of F, that f(x) must be the zero polynomial? It kind of just makes logical sense to me, so I can't think of a way to actually show this. please help
 
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Use that if f(a) = 0, then x-a divides f(x) in F[x] and show ultimately that any non-zero polynomial have a finite number of zeroes.
 
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