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 #3
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Nun zur Fläche:

$${\mathtt{Flaeche}} = {\frac{{\mathtt{1}}}{{\mathtt{4}}}}{\mathtt{\,\times\,}}{\sqrt{{\left[{{\mathtt{a}}}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{{\mathtt{b}}}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{{\mathtt{c}}}^{{\mathtt{2}}}\right]}^{{\mathtt{2}}}{\mathtt{\,-\,}}{\mathtt{2}}{\mathtt{\,\times\,}}\left[{{\mathtt{a}}}^{{\mathtt{4}}}{\mathtt{\,\small\textbf+\,}}{{\mathtt{b}}}^{{\mathtt{4}}}{\mathtt{\,\small\textbf+\,}}{{\mathtt{c}}}^{{\mathtt{4}}}\right]}}$$

a = Strecke P(y1/y2) P(y2/y3) = $${\sqrt{{\left[\left({\frac{{\mathtt{4}}}{{\mathtt{3}}}}\right){\mathtt{\,\small\textbf+\,}}\left({\frac{{\mathtt{10}}}{{\mathtt{3}}}}\right)\right]}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{\left[{\mathtt{\,-\,}}\left({\frac{{\mathtt{1}}}{{\mathtt{3}}}}\right){\mathtt{\,\small\textbf+\,}}\left({\frac{{\mathtt{8}}}{{\mathtt{3}}}}\right)\right]}^{{\mathtt{2}}}}}$$

b = Strecke P(y2/y3) P(y3/y1) = $${\sqrt{{\left[{\mathtt{\,-\,}}\left({\frac{{\mathtt{10}}}{{\mathtt{3}}}}\right){\mathtt{\,\small\textbf+\,}}\left({\mathtt{1}}\right)\right]}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{\left[{\mathtt{\,-\,}}\left({\frac{{\mathtt{8}}}{{\mathtt{3}}}}\right){\mathtt{\,-\,}}\left({\mathtt{2}}\right)\right]}^{{\mathtt{2}}}}}$$

C = Strecke P(y3/y1) P(y1/y2) = $${\sqrt{{\left[{\mathtt{\,-\,}}\left({\mathtt{1}}\right){\mathtt{\,-\,}}\left({\frac{{\mathtt{4}}}{{\mathtt{3}}}}\right)\right]}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{\left[\left({\mathtt{2}}\right){\mathtt{\,\small\textbf+\,}}\left({\frac{{\mathtt{1}}}{{\mathtt{3}}}}\right)\right]}^{{\mathtt{2}}}}}$$

 

19.06.2015
 #2
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Nun zum Umfang:

P(y1/y2)=(4/3;-1/3)

P(y2/y3)=(-10/3;-8/3)

P(y3/y1)=(-1/2)

$${\mathtt{Strecke}} = {\sqrt{{\left[{\mathtt{x2}}{\mathtt{\,-\,}}{\mathtt{x1}}\right]}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{\left[{\mathtt{y2}}{\mathtt{\,-\,}}{\mathtt{y1}}\right]}^{{\mathtt{2}}}}}$$

Umfang = Strecke P(y1/y2) P(y2/y3) + Strecke P(y2/y3) P(y3/y1) + Strecke P(y3/y1) P(y1/y2) =

$${\mathtt{Umfang}} = {\sqrt{{\left[\left({\frac{{\mathtt{4}}}{{\mathtt{3}}}}\right){\mathtt{\,\small\textbf+\,}}\left({\frac{{\mathtt{10}}}{{\mathtt{3}}}}\right)\right]}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{\left[{\mathtt{\,-\,}}\left({\frac{{\mathtt{1}}}{{\mathtt{3}}}}\right){\mathtt{\,\small\textbf+\,}}\left({\frac{{\mathtt{8}}}{{\mathtt{3}}}}\right)\right]}^{{\mathtt{2}}}}}{\mathtt{\,\small\textbf+\,}}{\sqrt{{\left[{\mathtt{\,-\,}}\left({\frac{{\mathtt{10}}}{{\mathtt{3}}}}\right){\mathtt{\,\small\textbf+\,}}\left({\mathtt{1}}\right)\right]}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{\left[{\mathtt{\,-\,}}\left({\frac{{\mathtt{8}}}{{\mathtt{3}}}}\right){\mathtt{\,-\,}}\left({\mathtt{2}}\right)\right]}^{{\mathtt{2}}}}}{\mathtt{\,\small\textbf+\,}}{\sqrt{{\left[{\mathtt{\,-\,}}\left({\mathtt{1}}\right){\mathtt{\,-\,}}\left({\frac{{\mathtt{4}}}{{\mathtt{3}}}}\right)\right]}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{\left[\left({\mathtt{2}}\right){\mathtt{\,\small\textbf+\,}}\left({\frac{{\mathtt{1}}}{{\mathtt{3}}}}\right)\right]}^{{\mathtt{2}}}}} \Rightarrow {\mathtt{Umfang}} = {\mathtt{13.734\: \!815\: \!540\: \!536\: \!239\: \!6}}$$

Schaut bitte mal drüber ob alles stimmt.

19.06.2015
 #1
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y (1) = -x+1
y (2) =-1/2*x-1
y (3) = 2*x+4

Erstmal würde ich die Schnittpunkte berechnen:

$$\underset{\,\,\,\,{\textcolor[rgb]{0.66,0.66,0.66}{\rightarrow {\mathtt{y, x}}}}}{{solve}}{\left(\begin{array}{l}{\mathtt{y}}={\mathtt{\,-\,}}{\mathtt{x}}{\mathtt{\,\small\textbf+\,}}{\mathtt{1}}\\
{\mathtt{y}}={\frac{{\mathtt{1}}}{{\mathtt{2}}}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,-\,}}{\mathtt{1}}\end{array}\right)} \Rightarrow \left\{ \begin{array}{l}{\mathtt{y}} = {\mathtt{\,-\,}}{\frac{{\mathtt{1}}}{{\mathtt{3}}}}\\
{\mathtt{x}} = {\frac{{\mathtt{4}}}{{\mathtt{3}}}}\\
\end{array} \right\} \Rightarrow \left\{ \begin{array}{l}{\mathtt{y}} = -{\mathtt{0.333\: \!333\: \!333\: \!333\: \!333\: \!3}}\\
{\mathtt{x}} = {\mathtt{1.333\: \!333\: \!333\: \!333\: \!333\: \!3}}\\
\end{array} \right\}$$

$$\underset{\,\,\,\,{\textcolor[rgb]{0.66,0.66,0.66}{\rightarrow {\mathtt{y, x}}}}}{{solve}}{\left(\begin{array}{l}{\mathtt{y}}={\frac{{\mathtt{1}}}{{\mathtt{2}}}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,-\,}}{\mathtt{1}}\\
{\mathtt{y}}={\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,\small\textbf+\,}}{\mathtt{4}}\end{array}\right)} \Rightarrow \left\{ \begin{array}{l}{\mathtt{y}} = {\mathtt{\,-\,}}{\frac{{\mathtt{8}}}{{\mathtt{3}}}}\\
{\mathtt{x}} = {\mathtt{\,-\,}}{\frac{{\mathtt{10}}}{{\mathtt{3}}}}\\
\end{array} \right\} \Rightarrow \left\{ \begin{array}{l}{\mathtt{y}} = -{\mathtt{2.666\: \!666\: \!666\: \!666\: \!666\: \!7}}\\
{\mathtt{x}} = -{\mathtt{3.333\: \!333\: \!333\: \!333\: \!333\: \!3}}\\
\end{array} \right\}$$

$$\underset{\,\,\,\,{\textcolor[rgb]{0.66,0.66,0.66}{\rightarrow {\mathtt{y, x}}}}}{{solve}}{\left(\begin{array}{l}{\mathtt{y}}={\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,\small\textbf+\,}}{\mathtt{4}}\\
{\mathtt{y}}={\mathtt{\,-\,}}{\mathtt{x}}{\mathtt{\,\small\textbf+\,}}{\mathtt{1}}\end{array}\right)} \Rightarrow \left\{ \begin{array}{l}{\mathtt{y}} = {\mathtt{2}}\\
{\mathtt{x}} = -{\mathtt{1}}\\
\end{array} \right\}$$

Lasst mich nachdenken...

19.06.2015
18.06.2015
 #1
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18.06.2015
 #1
avatar+14538 
+3

lineare Funktion:   f(x) = mx + b

 

lineare Gleichungen:

 

http://www.mathe-trainer.de/Klasse8/Lineare_Gleichungen/Aufgabensammlung.htm

 

http://www.mathebibel.de/lineare-gleichungen-loesen

 

http://www.mathepower.com/gleichungen.php

 

lineare Gleichungen mit 2 Variablen ( Gleichungssysteme )

 

http://www.mathe-online.at/lernpfade/Lernpfad603/?kapitel=1

Wenn du dich schon ein wenig mit Steigungen (Slope) auskennst, hier ein einfaches "Spiel" :

http://tube.geogebra.org/m/1346215

Bitte schreibe kurz, ob du damit zurecht kommst.

 

Gruß radix !

18.06.2015

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