.
1. F(x,y)=0 (x,y), , .
: x = φ(t), y = φ(t) ()
: x2+y2 = a2
: x= r*cosφ, y= r*sinφ ()
2. .
:
. . OA+AB=OB; OA+OB=OC
. A-B = A+(-B)
. λ*A; |λ*A|=|λ|*|A|; λ*A , λ>0, , λ<0
, . ( 1. A≠0, B , .. B=λ*A, λ ).
, . ( 2. A B , C : C = λ*A+μ*B, ).
3. A, B C , D ( ) : D=λ*A+μ*B+ν*C, .
.
.
.
. .
:
(x1, y1,z1) + (x2, y2 z2) = (x1+x2, y1+y2, z1+z2)
λ(x, y, z) = (λx, λy, λz)
, 1, ( ).
, .
i,j,k .
3. A*B=|A|*|B|*cosφ. ( , ).
: , (=), A≠0, B≠0.
: A=(x1, y1, z1), B=(x2, y2, z2), A*B= x1*x2+y1*y2+z1*z2
4. AxB , :
1) |AxB|=|A|*|B|*sinφ=S , A B
2) : ) A,B; ) A,B,AxB .
0.
|
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: , i, j, k, x1, y1, z1, x2, y2, z2.
5. A,B,C ABC , ABC=(AxB)*C.
: , .
:
1) , .
2) ABC>0, A,B,C . ABC<0, A,B,C .
: A=(x1, y1, z1), B=(x2, y2, z2), C=(x3, y3, z3), ABC = , 1 x1 y1 z1, 2 - x2 y2 z2, 3 - x3 y3 z3.
6. :
1) :
: x = x0+L*t, y = y0+m*t (), (L,m) .
: (x-x0)/L = (y-y0)/m, (L,m) .
2) :
y-y0 = k(x-x0)
3) :
A(x-x0) + B(y-y0) = 0, (A,B) , (x-x0, y-y0) .
4)
Ax+By+C=0
7. :
1) :
A(x-x0) + B(y-y0) + C(z-z0) = 0, (x0, y0, z0) , (A,B,C) .
2)
Ax+By+Cz+D=0
8. :
1)
: x=x0+Lt, y=y0+mt, z=z0+nt (), (L,m,n) .
: (x-x0)/L=(y-y0)/m=(z-z0)/n
2)
A1x+B1y+C1z+D1=0, A2x+B2y+C2z+D2=0 (), (A1,B1,C1) (A2, B2, C2) ( )
9. , () , ó,
: x2/a2 + y2/b2 = 1, a>b
: x = a*cost + x0, y = a*sint + y0 ()
, () , , .
: x2/a2 y2/b2 = 1
: y = b/a *x
, () , ( ).
p .
: y2 = 2px (p>0).
10. :
x=x'cosα y'sinα + a, y=x'sinα + y'cosα + b ()
11. F(x,y,z) = 0 xyz, , .
|
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: (x-a)2+(y-b)2+(z-c)2=r2
(?)
, (), ().
F(x,y)=0 Oxyz , Oz, F(x,y)=0, z=0 ().
, (), () ().
( ): , , .. x=const, y=const, z=const.
12. , .
1) : x2/a2 + y2/b2 + z2/c2 = 1;
2) : x2/a2 + y2/b2 z2/c2 = 1;
3) : x2/a2 + y2/b2 z2/c2 = -1;
4) : x2/a2 + y2/b2 z2/c2 = 0;
5) : x2/p + y2/q = 2z (p>0, q>0);
6) : x2/a2 + y2/b2 = 1;
7) : x2/a2 y2/b2 = 1;
8) : y2 = 2px (p>0).
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13. mxn. (m , n )
, 0.
nxn.
, , ( ) , . .
, , , . .
(E) , , , 1, 0. 1.
. , , .
:
1) . A B C , : c i j = a i j + b i j.
2) . A = (a i j) λ R B = (bi j) , : bi j = λ*ai j.
. A = (ai j) mxk B = (bi j) kxn C = (ci j) mxn , : ci j = ai 1*b1 j + ai 2*b2 j + + ai k*bk j. (i j i- j- ).
:
det(AB) = det(A)*det(B)
, 0, , 0.
( ), = = .
: , , , .
-1 = 1/detA * (Ai j)t
:
1) AX = B, A .
A-1AX = A-1B
X = A-1B
2) XA = B,
XAA-1 = BA-1
X = BA-1
3) AXB = C, A,B
A-1AXBB-1 = A-1CB-1
X = A-1CB-1
14. Rn n (x1, x2 xn) ( ) , .
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:
1) : (x1, x2, , xn) + (y1, y2, , yn) = (x1+y1, x2+y2, , x3+y3)
2) : λ*(x1, x2, , xn) = (λx1, λx2, , λxn), λ R.
λ1a1 + λ2a2 + + λkak a1, a2, , ak λ1, λ2, , λk. , a1, a2, , ak λ1, λ2, , λk. a1, a2, , ak λ1, λ2, , λk.
a1, a2, , ak (k>=1) , λ1, λ2, , λk, 0, , λ1a1 + λ2a2 + + λkak = 0.
a1, a2, , ak (k>=1) , λ1a1 + λ2a2 + + λkak = 0 , λ1 = λ2 = = λk = 0.
:
1) : , .
2) : , .
() :
1) , .
2) (: , ).
: ) , ,
) , 2 , .
3) a1, a2, , ak , a1, a2, , ak, b , b a1, a2, , ak.
k>=2 : k>=2 , .
: .
k- . . k k . k. Ÿ k .
. ( )
.
:
1) ();
2) () , 0;
3) () (), () .
. .
. , , , .
:
1) ( ). , ;
2) ( m Rn). m Rn , m;
3) ( n Rn). n , 0;
4) m>n Rn ;
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5) a1, a2, , ak b1, b2, , bL, k<L.
Rn. n a1, a2, , an Rn , Rn.
Rn ():
e1 = (1, 0, 0, ., 0)
e2 = (0, 1, 0, ., 0)
............................
en = (0, 0, 0, ., 1)
15. m n x1, x2, , xn :
a11x1 + a12x2 + + a1nxn = b1,
a21x1 + a22x2 + +a2nxn = b2,
........................................
am1x1 + am2x2 + + am nxn = bm.
()
ai j ,
bi ,
mxn n , .
, , , .
, 0, .
, .
, .. .
( ), .
(ai j) (, )
x1
X= x2 -
xn
b1
= b2 -
bn
AX = B .
16. nxn :
a11x1 + a12x2 + + a1nxn = b1,
.........................................
an1x1 + an2x2 + + annxn = bn.
()
A(ai j) n.
Δ = detA .
Δj , Δ j- .
. Δ≠0, nxn , : xj = Δj / Δ
|) .
-. , , .. r(A) = r(Ᾱ).
, , , - .
, , - .
:
1) mxn: mxn , (r<n)
2) nxn: nxn , Δ = 0.
, .
1. L a, b, c..., ( ):
1) . a, b L a+b L ;
2) . a L λ R λa L a λ.
( L) e1, e2, , en, ( L) .
.
n N. L n-, n , n , dimL=n. L={0} dimL=0. . , , .
2. . n-r .
.
: x = C1E1+...+Cn - r En r, E1,...,En r , 1,...,n r .
3. L ( L), :
1) A(x+y) = Ax + Ay (x,y L)
2) A(λx) = λAx (x L, λ R)
y = Ax x.
|
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, , .
4. x L A, λ R , Ax = λx.
λ A, x ( x , λ).
.
, , , . .
det(A-λE) ( ), det(A-λE)=0 ( ).
:
1) .
2) - λE.