Proving Existence of x2=b for b≥0 in R

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The discussion centers on proving the existence of a non-negative real number x such that x² = b for b ≥ 0 in the real numbers (R). A suggested approach involves demonstrating that the function f(x) = x² is continuous, increasing, and unbounded on the interval [0, ∞). By applying the Intermediate Value Theorem, one can establish that for any non-negative b, there exists an x in [0, ∞) such that f(x) = b. This proof strategy effectively confirms the existence of such an x.

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kreil
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Prove that if b is greater than or equal to zero (b in R), there exists a non-negative real number x such that x2=b.

I really don't know where to go. I think I need to modify a proof done in a class that I missed, so if someone could just give me a few hints I'll fill in the rest.

Thanks
Josh
 
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How have you defined the reals?

Or maybe prove that on [0, infinity), the function x -> x2 is continuous, increasing, and unbounded, and apply intermediate value theorem.
 
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