User:Annlex/Mathproject

From WikiEducator
Jump to: navigation, search

CURVE SKETCHING


f(x)=x4+4x3+6x2+4x


-Roots:

0=x4+4x3+6x2+4x

0=x(x3+4x2+6x+4)

x1=0
x3+4x2+6x+4=0
x2=-2 (erraten)

Polynomdivision:

 (x3+4x2+6x+4):(x+2)= x2+2x+2
-(x3+2x2)
--------
2x2+6x
-(2x2+4x)
--------
2x+4
-(2x+4)
--------
000

x2+2x+2=0
x1,2=

Roots:NS1(0/0),NS2(-2/0)


-1. Derivation:

f´(x)=4x3+12x2+12x+4

0=4x3+12x2+12x+4

x1= - 1 (erraten)

 (4x3+12x2+12x+4) : (x+1) = 4x2+8x+4
-(4x3+4x2)
---------
8x2+12x
-(8x2+8x)
--------
4x+4
-(4x+4)
-------
000

quadratic equation:

4x2+8x+4=0

4(x2+2x+1)=0

4(x+1)2=0

x1=x2=x3=-1 (tripple root)


-2. Derivation:

f´´(x)=12x+24x+12

f´´(-1)=12-24+12=0 (no solution)


f´(0)=4 (positiv gradient)

-TIP(-1/-1) (absolute minimum)


-Wf=[-1;+unendlich[
-Df=[-unendlich;+unentlich[


-There is no symmrtry to the koordinate plane.


general procedure:

f(x):

-roots: find out when the y-value is zero
f(x)=0