$$$k + r$$$ 對 $$$k$$$ 的導數
您的輸入
求$$$\frac{d}{dk} \left(k + r\right)$$$。
解答
和/差的導數等於導數的和/差:
$${\color{red}\left(\frac{d}{dk} \left(k + r\right)\right)} = {\color{red}\left(\frac{d}{dk} \left(k\right) + \frac{dr}{dk}\right)}$$常數的導數為$$$0$$$:
$${\color{red}\left(\frac{dr}{dk}\right)} + \frac{d}{dk} \left(k\right) = {\color{red}\left(0\right)} + \frac{d}{dk} \left(k\right)$$套用冪次法則 $$$\frac{d}{dk} \left(k^{n}\right) = n k^{n - 1}$$$,取 $$$n = 1$$$,也就是 $$$\frac{d}{dk} \left(k\right) = 1$$$:
$${\color{red}\left(\frac{d}{dk} \left(k\right)\right)} = {\color{red}\left(1\right)}$$因此,$$$\frac{d}{dk} \left(k + r\right) = 1$$$。
答案
$$$\frac{d}{dk} \left(k + r\right) = 1$$$A