Calculate the arc length of the vector function

In summary, the arc length of <2t,t^2,lnt> from 1=<t=<e can be calculated using the formula ∫√{(x')^2 + (y')^2 + (z')^2}dt. After factoring the expression in the integrand, it becomes ∫√{(2t + 1/t)^2}dt. To integrate this, you can use the substitution method or the power rule for indefinite integrals.
  • #1
jaydnul
558
15

Homework Statement


Calculate the arc length of [itex]<2t,t^2,lnt>[/itex] from [itex]1=<t=<e[/itex]

Homework Equations


Arc length=[itex]∫√{(x')^2 + (y')^2 + (z')^2}[/itex]

The Attempt at a Solution


So I have gotten to this point:
[itex]∫√{4 + 4t^2 + \frac{1}{t^2}}[/itex]

Am I on the right track, and if so, how do I integrate that?
 
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  • #2
Jd0g33 said:

Homework Statement


Calculate the arc length of [itex]<2t,t^2,lnt>[/itex] from [itex]1=<t=<e[/itex]

Homework Equations


Arc length=[itex]∫√{(x')^2 + (y')^2 + (z')^2}[/itex]
Missing dt in the integrand.

Also, if you use \sqrt instead of √, it will look better.
$$\int \sqrt{x'^2 + y'^2 + z'^2}dt $$
Jd0g33 said:

The Attempt at a Solution


So I have gotten to this point:
[itex]∫√{4 + 4t^2 + \frac{1}{t^2}}[/itex]

Am I on the right track, and if so, how do I integrate that?
Write the quantity in the radical as 4t2 + 4 + 1/t2, and then factor it.
 
  • #3
Thanks. Good advice so far. I think I might just be an idiot by how do you factor that? Haven't had to do that for a while.
 
  • #4
Nevermind, got it. multiply t^2
 
  • #5
Thanks for the help!
 
  • #6
Jd0g33 said:
Nevermind, got it. multiply t^2
You can't do that, but you can multiply by t2 over itself. OTOH, the expression can be factored directly, to (2t + 1/t)2.
 

FAQ: Calculate the arc length of the vector function

What is the definition of arc length?

Arc length is the distance along a curve or arc, measured as the length of the curve from one point to another.

What is a vector function?

A vector function is a mathematical function that takes in one or more inputs and produces a vector output.

How do you calculate the arc length of a vector function?

The arc length of a vector function can be calculated using the formula:
S = ∫√(1 + f'(x)^2)dx
where f'(x) is the derivative of the vector function and the integral is taken over the given interval.

Can the arc length of a vector function be negative?

No, the arc length of a vector function cannot be negative as it represents a physical distance and must be positive.

What is the significance of calculating the arc length of a vector function?

Calculating the arc length of a vector function is important in many fields of science and engineering, as it helps in understanding the shape and properties of curves, calculating work done by a force, and finding the shortest distance between two points in space.

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