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- .
18.19. - . - , / 2 . - .
y-y1=k1(x-x1)
y=k1x-k1x1+y1
y1-k1x1=b
y=k1x+b
- k.
2 M1(x1,y1), M2(x2,y2) x1¹x2, y1¹y2. 12 , 1: y-y1=k(x-x1). .. 2 , , 2 1: y-y1=k(x-x1) k:
:
:
- - , / 2
20,21. / . || ^.
)
S1 {l1,m1} S2 {l2,m2},
p:y=k1x+b1, k1=tgj1
q:y=k2x+b2, k2=tgj2 =>tgj=tg(j2-j1)=
=(tgj2-tgj1)/(1+ tgj1tgj2)=
=(k2-k1)/(1+k1k2).
) p||q, tgj=0, k1=k2
)p^q,
.
1. Ax+By+C=0, M0(x0,y0)
2. - Ax+By+Cz+D=0
2- .
2 -:
Ax2+2Bxy+Cy2+2Dx+2Ey+F=0,
) -
- -
a=b, x2+b2=a2 - - .
) - : x2/a2-y2/b2=1
) - : y2=2px y=ax2
) - : x2+y2+z2=2 (r2=(x-a)2+(y-b)2+(z-c)2)
) - : x2/a2-y2/b2+z2/c2=1
.
, y=ax2, - , - . , . .
. (0,0), -
y2=2px- .
2=2p- .
F(p/2,0) . , x=-p/2 - .
(,), , = r=p/2
-:
1. . ¥ , y=ax2.
25. -:
. L
x2+Cy2=d
.-
. . .- , = - 2+y2=2
F1(-c,0) F2(c,0) - . .
e=/ . (0<=e<=1)
|
|
A1,A2,B1,B2 - .
-:
, =2.
-.
2 . , - Ax2+Cy2=d, , .. *<0
) d>0, - : x2/a2-y2/b2=1, F1(c,o) F2(-c,0) - , e>0, e=c/a - .
-:
= 2.
) d=0, - x2/a2-y2/b2=0, 2 //b=0
) d<0, x2/a2-y2/b2=-1 - - .