16
1. .
:
2x-y > -1
2x-y < 1
x+y≠0
y < 2x+1
y > 2x-1
x≠y
1- .
2. , .
.
dz/dx=(6tg^2(2x-3y))/(cos^2(2x-3y))
dz/dy=(-9tg^2(2x-3y))/ (cos^2(2x-3y))
,
3*((6tg^2(2x-3y))/(cos^2(2x-3y)))+2*((-9tg^2(2x-3y))/cos^2(2x-3y))=(18tg^2(2x-3y))/(cos^2(2x-3y))-(18tg^2(2x-3y)))/(cos^2(2x-3y))=0
3. . ;
.
dz/dt=(dz/dx)*(dx/dt)+(dz/dy)*(dy/dt)=(x*e^x+e^x-e^x*y)*t-e^x
dz/dt=t*(sin t*esin t+ esin t- esin t*cos t)- esin t
4. .
.
.
, .
.
. , ,
Y C
B x
1 3
AB: y=0 -1 < x < 3
BC: y=x+1 0 < y < 4
CA: x=3 0 < y < 4
Z(y)=2x-2y=0
Z(x)=2x+2y-4=0
Y=1
x=1
O(1;1) z(1;1)=-2
Y=0 (x^2-4x)=2x-4 x=2 (2;0)
X=3 (9+6y-y^2-12)=6-2y y=3 (3;3)
Y=x+1 (x^2+2x(x+1)-(x+1)-4x)=(x^2+2x^2+2x-x^2-x-1-4x)=(2x^2-3x-1)=4x-3 x=3/4 y=7/4
Z(2;0)=4+0+0-8=-4
Z(3;3)=9+18-9-12=6
Z(3/4;7/4)=9/16+2*21/16-49/16-4*3/4=25/8
(2;0), (3;3)
6.
:
L(X, λ) = x*y + λ*(x^2+y^2-2)
∂L/∂x = 2*λ+y = 0
∂L/∂x2 = x+2*λ = 0
∂L/∂λ = x^2+y^2-2 = 0
:
0 1 2 0
1 0 2 0
1 1 0 2
3- (-1). 3- 2-:
0 1 2 0
0 -1 2 -2
1 1 0 2
2- 1-:
0 0 4 -2
0 -1 2 -2
1 1 0 2
1- x3
λ = -2/4 = -0.5
2- x2
|
|
y = -1/-1 = 1
3- x1
x = 1/1 = 1
(1;3). F(1;1)=1.
.
. , :
, ;
: F(x,y,z)=z^2+2xy-y^2+4z-1=0
.
(dF/dx)M0=(2y)(1,1,-4)=2
(dF/dy)M0=(2x-2y)(1,1,-4)=0.
(dF/dz)M0=(2z+4)(1,1,-4)=-4.
8. H :
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; .
.
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:
.