2003 AMC 10A Problem 9

Below is the professionally curated solution for Problem 9 of the 2003 AMC 10A, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2003 AMC 10A solutions, or check the answer key.

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Concepts:radicalexponent

Difficulty rating: 1350

9.

Simplify xxxx333.\sqrt[3]{x\sqrt[3]{x\sqrt[3]{x\sqrt{x}}}}.

x\sqrt{x}

x23\sqrt[3]{x^2}

x227\sqrt[27]{x^2}

x54\sqrt[54]{x}

x8081\sqrt[81]{x^{80}}

Solution:

Working outward, xx=x3/2,x\sqrt{x} = x^{3/2}, and its cube root is x1/2.x^{1/2}.

Then xx1/2=x3/2,x \cdot x^{1/2} = x^{3/2}, whose cube root is again x1/2.x^{1/2}.

Repeating once more, xx1/2=x3/2,x \cdot x^{1/2} = x^{3/2}, whose cube root is x1/2=x.x^{1/2} = \sqrt{x}.

Thus, the correct answer is A.

Problem 9 in Other Years