Mister Exam

Derivative of ylny

Function f() - derivative -N order at the point
v

The graph:

from to

Piecewise:

The solution

You have entered [src]
y*log(y)
ylog(y)y \log{\left(y \right)}
d           
--(y*log(y))
dy          
ddyylog(y)\frac{d}{d y} y \log{\left(y \right)}
Detail solution
  1. Apply the product rule:

    ddyf(y)g(y)=f(y)ddyg(y)+g(y)ddyf(y)\frac{d}{d y} f{\left(y \right)} g{\left(y \right)} = f{\left(y \right)} \frac{d}{d y} g{\left(y \right)} + g{\left(y \right)} \frac{d}{d y} f{\left(y \right)}

    f(y)=yf{\left(y \right)} = y; to find ddyf(y)\frac{d}{d y} f{\left(y \right)}:

    1. Apply the power rule: yy goes to 11

    g(y)=log(y)g{\left(y \right)} = \log{\left(y \right)}; to find ddyg(y)\frac{d}{d y} g{\left(y \right)}:

    1. The derivative of log(y)\log{\left(y \right)} is 1y\frac{1}{y}.

    The result is: log(y)+1\log{\left(y \right)} + 1


The answer is:

log(y)+1\log{\left(y \right)} + 1

The graph
02468-8-6-4-2-1010-2525
The first derivative [src]
1 + log(y)
log(y)+1\log{\left(y \right)} + 1
The second derivative [src]
1
-
y
1y\frac{1}{y}
The third derivative [src]
-1 
---
  2
 y 
1y2- \frac{1}{y^{2}}
The graph
Derivative of ylny