式子x^3/6+o(x^3)的2/3次方等於多少,

式子x^3/6+o(x^3)的2/3次方等於多少,

x^3+o(x^3)=x^3(1+o(1))
從而(x^3(1+o(1)))^2/3=x^2(1+o(1))^2/3=x^2(1+2/3*o(1))=x^2(1+o(1))=x^2+o(x^2).
這裡省略了係數1/6,可自行加上.