$$$a^{\sqrt{x}}$$$ 對 $$$x$$$ 的導數
您的輸入
求$$$\frac{d}{dx} \left(a^{\sqrt{x}}\right)$$$。
解答
函數 $$$a^{\sqrt{x}}$$$ 是兩個函數 $$$f{\left(u \right)} = a^{u}$$$ 與 $$$g{\left(x \right)} = \sqrt{x}$$$ 之複合 $$$f{\left(g{\left(x \right)} \right)}$$$。
應用鏈式法則 $$$\frac{d}{dx} \left(f{\left(g{\left(x \right)} \right)}\right) = \frac{d}{du} \left(f{\left(u \right)}\right) \frac{d}{dx} \left(g{\left(x \right)}\right)$$$：
$${\color{red}\left(\frac{d}{dx} \left(a^{\sqrt{x}}\right)\right)} = {\color{red}\left(\frac{d}{du} \left(a^{u}\right) \frac{d}{dx} \left(\sqrt{x}\right)\right)}$$套用指數法則 $$$\frac{d}{du} \left(n^{u}\right) = n^{u} \ln\left(n\right)$$$，令 $$$n = a$$$：
$${\color{red}\left(\frac{d}{du} \left(a^{u}\right)\right)} \frac{d}{dx} \left(\sqrt{x}\right) = {\color{red}\left(a^{u} \ln\left(a\right)\right)} \frac{d}{dx} \left(\sqrt{x}\right)$$返回原變數：
$$a^{{\color{red}\left(u\right)}} \ln\left(a\right) \frac{d}{dx} \left(\sqrt{x}\right) = a^{{\color{red}\left(\sqrt{x}\right)}} \ln\left(a\right) \frac{d}{dx} \left(\sqrt{x}\right)$$套用冪次法則 $$$\frac{d}{dx} \left(x^{n}\right) = n x^{n - 1}$$$，取 $$$n = \frac{1}{2}$$$：
$$a^{\sqrt{x}} \ln\left(a\right) {\color{red}\left(\frac{d}{dx} \left(\sqrt{x}\right)\right)} = a^{\sqrt{x}} \ln\left(a\right) {\color{red}\left(\frac{1}{2 \sqrt{x}}\right)}$$因此，$$$\frac{d}{dx} \left(a^{\sqrt{x}}\right) = \frac{a^{\sqrt{x}} \ln\left(a\right)}{2 \sqrt{x}}$$$。
答案
$$$\frac{d}{dx} \left(a^{\sqrt{x}}\right) = \frac{a^{\sqrt{x}} \ln\left(a\right)}{2 \sqrt{x}}$$$A