P:A1x+B1y+C1z+D1=0
Q:A2x+B2y+C2z+D2=0
- .
,
- ,
:
1. :
Z=0
M0(x0,y0,0), .. Z=0
2. S -?
P^ N1 {A1,B1,C1}
Q^ N1 {A2,B2,C2}
S = N1 * N2
.
P:A1x+B1y+C1z+D1=0^ N1 {A1,B1}
Q:A2x+B2y+C2z+D2=0^ N2 {A2,B2}
)
)
pq<=> N1 || N2, A1/A2=B1/B2
)
p||q<=> N1 ^ N2, A1A2+B1B2=0
-
. .
- ,
^ .
M0(x0,y0)
M0M {x-x0,y-y0}
n* M0M =0
A(x-x0)+B(y-y0)=0
Ax+By-Ax0-By0=0
-Ax0-By0=C
Ax+By+C=0-
- .
- , / 2 .