SKKU-Calculus-Sec-15-6 Surface Area by SGLee with 김유경
15.6 Surface Area by SGLee with 김유경

![]()

1-3. Find a parametric representation of the surface.
1. ![]()
Let the parameters
and
,
we find that parametric surface is given by equations
,
and
.
Therefore, the plane is described by the vector function
.
2.
.
Let the parameters
and
,
we find that parametric surface is given by equations
,
and
.
Therefore, the plane is described by the vector function
.
3. The portion
from
to
.
4-5. Find an equation of the tangent plane at the point on the surface corresponding to the given parameter values.
4.
,
,
,
,
.
![]()
At
and
, the point on the surface is
. The surface is defined by the vector function
![]()
, then
,
and
.
The normal vector
to the surface at
and
. An equation of the tangent plane at that point is
or
.
Note : 처음에 a,b,c를 x,y,z를 놓지않아야 한다. x,y,z라고 놓게 되면, tangent plane이 u,v에 관한 함수로 나오게 되어서 제대로 답을 구할 수 없다.
5.
;
,
.
6-8. Calculate the area of the surface.
|
6. The surface with parametric equations
,
,
,
,
.
![]()
![]()
![]()
![]()
and then form the cross product
![]()
![]()
The area is
![]()
![]()
.
7. The part of the plane
that lines in the first octant.
8. The part of the plane
tha lines inside the cylinder
.