RT,求证当 f(x)=xαf\left(x\right)=x^\alphaf(x)=xα 时,f′(x)=αxα−1f'\left(x\right)=\alpha x^{\alpha-1}f′(x)=αxα−1 对于任意 α∈Q\alpha\in\mathbb{Q}α∈Q 都成立时,有如下等式:
limΔx→0xα(eα⋅Δxx−1)Δx=limΔx→0xα(1+α⋅Δxx−1)Δx\lim_{\Delta x \to 0} \dfrac{x ^ \alpha \left (e ^ {\alpha \cdot \frac{\Delta x}{x} } -1 \right ) }{\Delta x} =\lim_{\Delta x \to 0} \dfrac{x ^ \alpha \left (1 + \alpha \cdot \frac{\Delta x}{x} - 1 \right ) }{\Delta x} limΔx→0Δxxα(eα⋅xΔx−1)=limΔx→0Δxxα(1+α⋅xΔx−1)
求问各位大佬为什么成立?