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.
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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 .