Mister Exam

Other calculators


x^3*e^(-x)

You entered:

x^3*e^(-x)

What you mean?

Derivative of x^3*e^(-x)

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

The graph:

from to

Piecewise:

The solution

You have entered [src]
 3  -x
x *e  
x3exx^{3} e^{- x}
d / 3  -x\
--\x *e  /
dx        
ddxx3ex\frac{d}{d x} x^{3} e^{- x}
Detail solution
  1. Apply the quotient rule, which is:

    ddxf(x)g(x)=f(x)ddxg(x)+g(x)ddxf(x)g2(x)\frac{d}{d x} \frac{f{\left(x \right)}}{g{\left(x \right)}} = \frac{- f{\left(x \right)} \frac{d}{d x} g{\left(x \right)} + g{\left(x \right)} \frac{d}{d x} f{\left(x \right)}}{g^{2}{\left(x \right)}}

    f(x)=x3f{\left(x \right)} = x^{3} and g(x)=exg{\left(x \right)} = e^{x}.

    To find ddxf(x)\frac{d}{d x} f{\left(x \right)}:

    1. Apply the power rule: x3x^{3} goes to 3x23 x^{2}

    To find ddxg(x)\frac{d}{d x} g{\left(x \right)}:

    1. The derivative of exe^{x} is itself.

    Now plug in to the quotient rule:

    (x3ex+3x2ex)e2x\left(- x^{3} e^{x} + 3 x^{2} e^{x}\right) e^{- 2 x}

  2. Now simplify:

    x2(3x)exx^{2} \cdot \left(3 - x\right) e^{- x}


The answer is:

x2(3x)exx^{2} \cdot \left(3 - x\right) e^{- x}

The graph
02468-8-6-4-2-1010-5000000050000000
The first derivative [src]
   3  -x      2  -x
- x *e   + 3*x *e  
x3ex+3x2ex- x^{3} e^{- x} + 3 x^{2} e^{- x}
The second derivative [src]
  /     2      \  -x
x*\6 + x  - 6*x/*e  
x(x26x+6)exx \left(x^{2} - 6 x + 6\right) e^{- x}
The third derivative [src]
/     3             2\  -x
\6 - x  - 18*x + 9*x /*e  
(x3+9x218x+6)ex\left(- x^{3} + 9 x^{2} - 18 x + 6\right) e^{- x}
The graph
Derivative of x^3*e^(-x)