Green's Theorem in 3 dimensions problem

In summary, the conversation discusses the evaluation of a line integral using the standard definition and the fundamental theorem of line integrals. The parametric equation for the given curve is provided, allowing for the functions x, y, and z to be expressed in terms of t. The final solution is \frac{4}{5}.
  • #1
duki
264
0

Homework Statement



Evaluate: [tex] \int _C{xydx - yzdy + xzdz}[/tex]
C: [tex]\vec{r}(t) = t\vec{i} + t^2\vec{j} + t^4\vec{k}[/tex]
o <= t <= 1

Homework Equations



The Attempt at a Solution



I understand that you cannot use Green's Theorem in 3 dimensions. How else can I go about solving this?
 
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  • #2


Just use the standard definition of a "line integral".

On C, x= t, y= t2, and z= t4
dx= dt, dy= 2tdt, and dz= 4t3.

xydx- yzdy+ xzdz= (t)(t2)dt- (t2)(t4)(2tdt)+ (t)(t4)(4t3dt.

Integrate that from t= 0 to t= 1.
 
  • #3


Ohhh snap. I remember talking about the fundamental theorem of line integrals now. Thanks!
 
  • #4


[itex]x[/itex], [itex]y[/itex] and [itex]z[/itex] will all be functions of [itex]t[/itex] along the curve...You should be able to simply look at the parametric equation for your curve [itex]\vec{r}(t) = t\hat{i} + t^2\hat{j} + t^4\hat{k}[/itex] and read off what those functions are.:wink:...Then you can easily express [itex]dx[/itex], [itex]dy[/itex] and [itex]dz[/itex] in terms of [itex]dt[/itex] and you integral will simply be a single variable integration...

EDIT: Halls beat me to it.
 
  • #5


Ok so I got:

EDIT:
[tex]\int _0^1{4t^4 dt} = \frac{4t^5}{5} => \frac{4}{5}[/tex] ?
 
Last edited:

What is Green's Theorem in 3 dimensions problem?

Green's Theorem in 3 dimensions problem is a mathematical concept that relates the surface integral of a vector field over a closed surface to the volume integral of the divergence of the same vector field over the region enclosed by the surface.

What is the significance of Green's Theorem in 3 dimensions problem?

Green's Theorem in 3 dimensions problem is an important tool in vector calculus and is often used in physics and engineering to solve problems involving the flow of fluids and electric fields.

How is Green's Theorem in 3 dimensions problem different from the 2-dimensional version?

The 2-dimensional version of Green's Theorem only applies to closed curves in the xy-plane, while the 3-dimensional version applies to closed surfaces in 3-dimensional space.

What is the formula for Green's Theorem in 3 dimensions problem?

The formula for Green's Theorem in 3 dimensions problem is:
∭(div F)dV = ∮F · dS

What are some real-life applications of Green's Theorem in 3 dimensions problem?

Green's Theorem in 3 dimensions problem has various practical applications, such as calculating fluid flow through a 3-dimensional region, determining the electric flux through a closed surface, and finding the mass of a 3-dimensional object with a varying density function.

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