點解負次方o既數成舊擺落分母會變做正次方o既數

假設 n > 0

a⁻ⁿ

= a⁰⁻ⁿ ...... (因為 -n = 0 - n)

= a⁰ / aⁿ...... (因為 aᵝ⁻ᵞ = aᵝ /aᵞ)

= 1 / aⁿ ...... (因為 a⁰ = 1)

Suppose n > 0

(1/a)⁽⁻ⁿ⁾
=(a⁻¹)⁽⁻ⁿ⁾
=a⁽⁻¹⁾⁽⁻ⁿ⁾
=aⁿ