Question

(-1supra2)la puterea a-4a.

Answer 1

$\it \left(-\dfrac{1}{2}\right)^4 = \left(\dfrac{1}{2}\right)^4 = \dfrac{1^4}{2^4} = \dfrac{1}{16}$

Un număr negativ ridicat la o putere pară dă rezultatul pozitiv.

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[tex]\it \left(-\dfrac{1}{2}\right)^{-4} = \left[\left(-\dfrac{1}{2}\right)^4\right]^{-1} =\left[\left(\dfrac{1}{2}\right)^4\right]^{-1}= \left(\dfrac{1^4}{2^4}\right)^{-1} = \left(\dfrac{1}{16}\right)^{-1} = \\\;\\ \\\;\\ = \dfrac{16}{1}=16[/tex]

Observație:

$\it \left(\dfrac{a}{b}\right)^{-1} = \dfrac{b}{a}$