# Homework Help: Line Integral

1. Nov 29, 2005

### Weatherkid11

Find the exact value of http://forums.cramster.com/Answer-Board/Image/cramster-equation-20051129112586326885897811250007777.gif [Broken] where http://forums.cramster.com/Answer-Board/Image/cramster-equation-20051129110356326885883583125005816.gif [Broken] and C is the line segment from (1,2,1) to (6,4,5).
i, j, k are unit vectors
So far all i have done is drawn in the line segment on a 3D graph.. Look at the URLS for the integral and the F(x,y,z)

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2. Nov 29, 2005

### amcavoy

$$\int_C\mathbf{F}\cdot d\mathbf{r}$$

$$\mathbf{F}=\left<x^4e^y,\,\ln{z},\,\sqrt{y^2+z^2}\right>$$

$$\mathbf{r}=\left<1+5t,\,2+2t,\,1+4t\right>;\quad 0\leq t \leq 1$$

Can you figure it out from here?

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3. Nov 29, 2005

### Weatherkid11

OK i worked off of what you got and i got
http://www.freemathhelp.com/forum/mimetex/pictures/d1183703930c2d1a7c5a37255ca42e49.gif [Broken]
But this integral looks VERY hard to solve

Last edited by a moderator: May 2, 2017
4. Nov 30, 2005

### arildno

A few hints:
For the first term, use integration-by-parts, and for the third term, complete the square in the form: $K\sqrt{(t+a)^{2}+b}$, where K,a,b are appropriate constants. Dependent upon the sign of b, we may write $b=\pm{c}^{2}$ where c is some constant.

See if you manage to make the last few steps on your own..

Last edited by a moderator: May 2, 2017