Question

Chứng tỏ rằng a^-n = 1/ a^n

Answer 1

\(a^{-n}=a^{n-2n}=\dfrac{a^n}{a^{2n}}=\dfrac{a^n}{a^n.a^n}=\dfrac{1}{a^n};\left(a\ne0\right)\)

Answer 2

\(\begin{equation} a^{-n} = a^{n-2n} = \frac{a^{n}}{a^{2n}} = \frac{a^{n}}{a^{n} \cdot a^{n}} = \frac{1}{a^{n}}; \quad (a \neq 0) \end{equation} \)