Exercise · ZW-INTERMEDIATE-VALUE-THEOREM-002 · ★☆☆ Basic

Let \(f(x)=x^{2}-3\). On which interval does the intermediate value theorem guarantee a root?

Choose one option.

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  • D. \([1,2]\)

Explanation

f is continuous on all of ℝ. Only on \([1,2]\) do the endpoint values have opposite signs (f(1) = -2, f(2) = 1), so by the intermediate value theorem there is a root there. On the other intervals the signs agree and the theorem guarantees nothing.

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Review the concept: Intermediate value theorem

If \(f\) is continuous on \([a,b]\) and \(N\) lies between \(f(a)\) and \(f(b)\), there is some \(c\in(a,b)\) with \(f(c)=N\).

\[f\ \text{continuous on }[a,b],\ f(a)

More practice problems: intermediate value theorem

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