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xe^(-x/2)
Plotting a function graph/ xe^(-x/2)

Graphing y = xe^(-x/2)

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The graph:

from to

Intersection points:

does show?

Piecewise:

The solution

You have entered [src] 
          -x 
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           2 
f(x) = x*e
f(x)=xe(−1)x2f{\left(x \right)} = x e^{\frac{\left(-1\right) x}{2}} 
f = x*E^(-x/2)
The graph of the function
0102030405060708090100110120130-10-20002000
The points of intersection with the X-axis coordinate
Graph of the function intersects the axis X at f = 0
so we need to solve the equation:
xe(−1)x2=0x e^{\frac{\left(-1\right) x}{2}} = 0
Solve this equation
The points of intersection with the axis X:

Analytical solution
x1=0x_{1} = 0
Numerical solution
x1=138.943848589893x_{1} = 138.943848589893
x2=132.985816431156x_{2} = 132.985816431156
x3=91.5054628829366x_{3} = 91.5054628829366
x4=101.326683040058x_{4} = 101.326683040058
x5=136.957325310529x_{5} = 136.957325310529
x6=119.105269897573x_{6} = 119.105269897573
x7=113.168557011776x_{7} = 113.168557011776
x8=74.0392717219567x_{8} = 74.0392717219567
x9=77.5601992651609x_{9} = 77.5601992651609
x10=97.3918261051326x_{10} = 97.3918261051326
x11=129.016562623174x_{11} = 129.016562623174
x12=111.191701047147x_{12} = 111.191701047147
x13=89.5484716110773x_{13} = 89.5484716110773
x14=87.5945090232618x_{14} = 87.5945090232618
x15=83.6970973965431x_{15} = 83.6970973965431
x16=123.067540388527x_{16} = 123.067540388527
x17=140.930847885457x_{17} = 140.930847885457
x18=93.4651859652441x_{18} = 93.4651859652441
x19=117.125411922138x_{19} = 117.125411922138
x20=103.296764962881x_{20} = 103.296764962881
x21=109.215998787545x_{21} = 109.215998787545
x22=75.9582278615682x_{22} = 75.9582278615682
x23=105.268425321898x_{23} = 105.268425321898
x24=99.3583181793708x_{24} = 99.3583181793708
x25=0x_{25} = 0
x26=72.1286573308603x_{26} = 72.1286573308603
x27=115.146485250814x_{27} = 115.146485250814
x28=107.241540269193x_{28} = 107.241540269193
x29=70.2278341185476x_{29} = 70.2278341185476
x30=131.000891064693x_{30} = 131.000891064693
x31=95.427382421153x_{31} = 95.427382421153
x32=125.04984591054x_{32} = 125.04984591054
x33=79.816716308387x_{33} = 79.816716308387
x34=81.7545134822841x_{34} = 81.7545134822841
x35=142.918298209055x_{35} = 142.918298209055
x36=77.8843596511898x_{36} = 77.8843596511898
x37=127.032867683997x_{37} = 127.032867683997
x38=134.971304934036x_{38} = 134.971304934036
x39=66.4634017838308x_{39} = 66.4634017838308
x40=64.605232251426x_{40} = 64.605232251426
x41=121.08599800789x_{41} = 121.08599800789
x42=85.6439180738776x_{42} = 85.6439180738776
x43=68.3386317231503x_{43} = 68.3386317231503
The points of intersection with the Y axis coordinate
The graph crosses Y axis when x equals 0:
substitute x = 0 to x*E^(-x/2).
0e(−1)020 e^{\frac{\left(-1\right) 0}{2}}
The result:
f(0)=0f{\left(0 \right)} = 0
The point:
(0, 0)
Extrema of the function
In order to find the extrema, we need to solve the equation
ddxf(x)=0\frac{d}{d x} f{\left(x \right)} = 0
(the derivative equals zero),
and the roots of this equation are the extrema of this function:
ddxf(x)=\frac{d}{d x} f{\left(x \right)} =
the first derivative
−xe(−1)x22+e(−1)x2=0- \frac{x e^{\frac{\left(-1\right) x}{2}}}{2} + e^{\frac{\left(-1\right) x}{2}} = 0
Solve this equation
The roots of this equation
x1=2x_{1} = 2
The values of the extrema at the points:
       -1 
(2, 2*e  )


Intervals of increase and decrease of the function:
Let's find intervals where the function increases and decreases, as well as minima and maxima of the function, for this let's look how the function behaves itself in the extremas and at the slightest deviation from:
The function has no minima
Maxima of the function at points:
x1=2x_{1} = 2
Decreasing at intervals
(−∞,2]\left(-\infty, 2\right]
Increasing at intervals
[2,∞)\left[2, \infty\right)
Inflection points
Let's find the inflection points, we'll need to solve the equation for this
d2dx2f(x)=0\frac{d^{2}}{d x^{2}} f{\left(x \right)} = 0
(the second derivative equals zero),
the roots of this equation will be the inflection points for the specified function graph:
d2dx2f(x)=\frac{d^{2}}{d x^{2}} f{\left(x \right)} =
the second derivative
(x4−1)e−x2=0\left(\frac{x}{4} - 1\right) e^{- \frac{x}{2}} = 0
Solve this equation
The roots of this equation
x1=4x_{1} = 4

Сonvexity and concavity intervals:
Let’s find the intervals where the function is convex or concave, for this look at the behaviour of the function at the inflection points:
Concave at the intervals
[4,∞)\left[4, \infty\right)
Convex at the intervals
(−∞,4]\left(-\infty, 4\right]
Horizontal asymptotes
Let’s find horizontal asymptotes with help of the limits of this function at x->+oo and x->-oo
lim⁡x→−∞(xe(−1)x2)=−∞\lim_{x \to -\infty}\left(x e^{\frac{\left(-1\right) x}{2}}\right) = -\infty
Let's take the limit
so,
horizontal asymptote on the left doesn’t exist
lim⁡x→∞(xe(−1)x2)=0\lim_{x \to \infty}\left(x e^{\frac{\left(-1\right) x}{2}}\right) = 0
Let's take the limit
so,
equation of the horizontal asymptote on the right:
y=0y = 0
Inclined asymptotes
Inclined asymptote can be found by calculating the limit of x*E^(-x/2), divided by x at x->+oo and x ->-oo
lim⁡x→−∞e(−1)x2=∞\lim_{x \to -\infty} e^{\frac{\left(-1\right) x}{2}} = \infty
Let's take the limit
so,
inclined asymptote on the left doesn’t exist
lim⁡x→∞e(−1)x2=0\lim_{x \to \infty} e^{\frac{\left(-1\right) x}{2}} = 0
Let's take the limit
so,
inclined coincides with the horizontal asymptote on the left
Even and odd functions
Let's check, whether the function even or odd by using relations f = f(-x) и f = -f(-x).
So, check:
xe(−1)x2=−xex2x e^{\frac{\left(-1\right) x}{2}} = - x e^{\frac{x}{2}}
- No
xe(−1)x2=xex2x e^{\frac{\left(-1\right) x}{2}} = x e^{\frac{x}{2}}
- No
so, the function
not is
neither even, nor odd
The graph
Graphing y = xe^(-x/2)
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