Dany jest trójkąt A(1,1) B(−3,2) C(4,−6)
1.Wyznacz długość odcinka |AB|
|AB|=√((−3−1)2+(2−1)2
|AB|=√−42+12=√17
2.Wyznacz prostą AB w postaci ogólnej i kierunkowej
Najpierw kierunkowa:
(x2−x1)(y−y1)=(y2−y1)(x−x1)
(−3−1)(y−1)=(2−1)(x−1)
−4(y−1)=1(x−1)
−4y+4=x−1
−4y=x−5 /:(−4)
| x | 5 | |||
y= | − | |||
| −4 | −4 |
| x | 5 | |||
y=−( | )−(− | ) | ||
| 4 | 4 |
| x | 5 | |||
y=−( | )+ | |||
| 4 | 4 |
| x | 5 | |||
y+ | − | =0 ![]() | ||
| 4 | 4 |
| x | 5 | ||
+y− | =0 ![]() | ||
| 4 | 4 |
| 1+(−3) | 1+2 | |||
D=( | ), ( | ) | ||
| 2 | 2 |
| −2 | 3 | |||
D=( | ), ( | ) | ||
| 2 | 2 |
| 3 | ||
D=(−1), ( | ) | |
| 2 |
−6=4a+b /*(−1)
| 3 | |
=−a+b | |
| 2 |
| 3 | |
=−a+b | |
| 2 |
| 3 | ||
6 | =−5a | |
| 2 |
| 15 | |
=−5a /:(−5) | |
| 2 |
| 3 | ||
a=− | ![]() | |
| 2 |
| 3 | ||
rownanie prostej: y= − | x | |
| 2 |