What is the derivative of $y=x^y$
What is the derivative of $y=x^y$ ?
I have tried the below. Please correct me if I am wrong on any of the below.
$$y=x^y.$$
Taking natural log on both sides,
$$\log y = y \log x.$$
Differentiating on both sides,
$$\left(\frac1y - \log x\right) y' = \frac{y}x$$
$$y' = \frac{y}{(\frac{x}y) - x\log x}$$
$$y' = \frac{y^2}{x(1-y\log x)}$$
Finally,
$$y' = \frac{x^{2y}}{x(1-x^y\log x )}$$
$$y' = \frac{x^{2y-1}}{1-x^y \log x}.$$
$\endgroup$ 32 Answers
$\begingroup$$$y=e^{y\ln (x)} $$
$$\ln (y)=y\ln (x) $$
$$x=e^{\frac {\ln (y)}{y}} $$
differentiating wrt $x $, we find
$$1=x \frac {1-\ln (y)}{y^2}y'$$
thus
$$y'=\frac {y^2}{x (1-\ln (y))} $$
$\endgroup$ 3 $\begingroup$$$y'=(x^y)'=\left(e^{y\ln{x}}\right)'=x^y\left(y'\ln{x}+\frac{y}{x}\right),$$ which gives $$y'=\frac{yx^{y-1}}{1-x^y\ln{x}}$$
$\endgroup$ 5