Fun with derivatives

Calculus Level 1

If y = x x y = x^x , then find d y d x \dfrac{dy}{dx}

2 + log x 2 + \log x x x ( 1 + log x ) x^x (1 + \log x) log x \log x x x log x x^x \log x

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

2 solutions

Sarthak Rath
Mar 3, 2015

y = x x y=x^x can be written as log x y = x \log_x y = x

\Rightarrow log e y log e x = x \frac{\log_e y}{\log_e x}=x

\Rightarrow log y = x × l o g x \log y = x \times log x

differentiating both sides w.r.t x x , we get :

1 y × d y d x = x × 1 x + log x \frac{1}{y} \times \frac{dy}{dx} = x \times \frac{1}{x} + \log x

solving this for d y d x \frac{dy}{dx} , we get :

d y d x = y ( 1 + log x ) \frac{dy}{dx} = y(1 + \log x) -------------------------(1)

given, y = x x y=x^x -------------------------------------------(2)

hence, by substituting (2) in (1),

x x ( 1 + log x ) \boxed{x^x(1 + \log x) }

Lu Chee Ket
Jan 29, 2015

y = e^(x Ln x)

Let u = x Ln x, y = e^u

d u/ d x = Ln x + x (1/ x) = Ln x + 1

d y/ d u = e^u

d y/ d x = (d y/ d u)(d u/ d x) = e^(x Ln x)(Ln x + 1)

d y / d x = x^x (1 + Ln x)

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...