What is Arc length: Definition and 286 Discussions

Arc length is the distance between two points along a section of a curve.
Determining the length of an irregular arc segment is also called rectification of a curve. The advent of infinitesimal calculus led to a general formula that provides closed-form solutions in some cases.

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  1. R

    Finding Arc Length of y=x^{\frac{1}{2}}- \frac{1}{3}x^{\frac{3}{2}}+\lambda

    1.Homework Statement y=x^{\frac}{1}{2}}- \frac{1}{3}x^{\frac{3}{2}}+\lambda For 0 \leq x \leq 3 Show that the arc length,s=2\sqrt{3} Homework Equations s=\int_{x_1} ^{x_2} \sqrt{1+ (\frac{dy}{dx})^2} dx The Attempt at a Solution \frac{dy}{dx}=\frac{1}{2\sqrt{x}} -...
  2. C

    How Do I Integrate the Last Part of This Arc Length Equation?

    I'm working on this problem x^5/6+1/(10x^3) [1,2] and I got the equation: sqrt(1+(5x^4/6-3/10^4)^2) or sqrt(1+25x^8/36+9/100x^8-1/2) I'm not sure how to integrate the last part, is there some sort of obvious substitution I'm missing?
  3. A

    How do I calculate the arc length of a polar curve?

    It's easy question,but I don't know whether I solved it correctly. Homework Statement Calculate the length of the curve given by r=a\sin^3 \frac{\theta}{3} in polar coordinates. Here, a > 0 is some number. Homework Equations l=\int \sqrt{r^2(\theta)+(\frac{dr}{d\theta})^2}d\theta...
  4. B

    Arc Length around Helical Torus

    Can anybody help? Mathematical Physics. I'm seeking an analytical expression for the path length of a point that follows a helical path with the helix wound about an axis to form a torus. The arc path length of a helix is simple to compute, but when its formed into a torus there is a...
  5. T

    Arc length trig vector problem

    I need help with this homework problem: Making a turn, a jetliner flies 2.1km on a circular path of radius 3.4km. Through what angle does it turn? Any ideas that would help me in doing it?? thanks
  6. J

    How can I simplify this derivative to make calculating arc length easier?

    Hi! Here's my question on finding arc length. If I've taken the derivative correctly, is there anyway I can simplify it before putting it into the arc length formula? Homework Statement Find the arc length where 0\leqx\leq2 y=(x^{3}/3)+x^{2}+x+1/(4x+4) Homework Equations...
  7. L

    How Do You Calculate the Arc Length of y=sqrt(x^3)?

    [SOLVED] Arc Length Problem y=\sqrt{x^{3}} So you plug it into the formula for arc length. (integral of the sqrt of 1+y'^2) And it yields \int \sqrt{1+(\frac{3x^{2}}{2\sqrt{x^{3}}})^{2}dx From there you would use trig substitution, 1+tan^2theta = sec^2theta. But converting the dx to...
  8. N

    Arc Length of an Ellipse: Formula & Calculation

    Is there a general formula for calculating the arc length between two points along an ellipse?
  9. M

    Arc Length Curve: Find Point at Distance 26pi

    Homework Statement Find the point on the curve r(t) = (5Sint)i + (5Cost)j + 12tk at a distance 26pi units along the curve from the point (0,5,0) in the direction of increasing arc length. Homework Equations L = int (|v|) from 0 to T. The Attempt at a Solution T comes to be 2pi...
  10. B

    Understanding Polar Coordinates and Arc Length Equations

    Homework Statement My book says if you write a plane curve in polar coordinates by p = p(?), a<=?<=b then the arc length is ??(p^2+(p')^2)d? (the integral is from a to b). It doesn't tell me how they got this equation though and I can't figure it out myself. what does the equation p(?) mean...
  11. C

    Arc Length and Smooth Curves: Understanding the Basis for Assumptions

    Guys, I need your kind assistance. I am studying arcs length. Suppose a vectorial function with domain [a, b] (interval in R) and range in RxR. This range is a curve in the RxR plane. Take a partition P of [a, b]: a= t0, t1, t2,..., tn = b. We have a straight line which goes from F(t0) to...
  12. M

    What is the weight of a cable hanging between two poles?

    Homework Statement A cable hangs between two poles of equal height and 39 feet apart. At a point on the ground directly under the cable and x feet from the point on the ground halfway between the poles the height of the cable in feet is h(x)=10 +(0.4)( x^{1.5}) The cable weighs 12.5...
  13. P

    Using integrals to calculate arc length

    Homework Statement Just started Calc II last month, it's been smooth so far but I've run into a bit of snag involving the application of integrals in the calculation of arc length. The formula you use is the definite integral of (1+(d/dx)^2)^.5. Often once you derive the d/dx and...
  14. S

    What is the surface area when rotating a curve about the x-axis?

    1 Find the area bounded by the curve x = t - \frac{1}{t} , y = t + \frac{1}{t} and the line y = 2.5 . I know that A = \int_{\alpha}^{\beta} g(t)f'(t) \; dt I ended up with \int_{1}^{2} 2.5-(t+\frac{1}{t})(1+\frac{1}{t^{2}}) 2 Find the length of the curve: x = a(\cos \theta + \theta...
  15. C

    Calculating Arc Length for Given Equation with Integration Method

    If y = \frac{x^{3}}{6} + \frac{1}{2x}\ and \frac{1}{2}\leq x\leq 1 . Find the arc length. So \frac{dy}{dx} = \frac{x^{2}}{2} - \frac{1}{2x^{2}} . So I got \frac{1}{2} \int^{1}_{\frac{1}{2}} \sqrt{2+x^{4} + x^{-4}} dx . How would you evaulate this? Thanks
  16. D

    How to Simplify the Integral in an Arc Length Problem with Parametric Equations?

    Okay, so I was given the parametric equations of x = (cos(t))^2 and y = cos(t). So I found dy/dt = -sin(t) and dx/dt = -2sin(t)cos(t). This is where I am getting stuck, so I have the L = integral from 0 to 4pi (sqrt((dx/dt)^2+(dy/dt)^2)) , but I don't know how to simplify this to get the answer...
  17. B

    Arc Length for a metal project

    Hello everyone. I'm a metal worker trying to do the layout for a project using a few nice curves. To do that, I need to get arc length, but I'm having trouble finding it for f(x)=x^3. If anyone can give me a nudge in the right direction for integrating (1+(3x^2)^2)^1/2, it would be greatly...
  18. C

    Solving Arc Length Problem: 45 Degrees & x-Axis

    ..Or I think this is considered that... Here's the problem as written then I'll get to it: Find the length of the curve y^2=x^3 from the orign to the point where the tangent makes an angle of 45 degrees with the x-axis. Okay, by me posting this, I don't want anyone (nor am I looking for...
  19. K

    Arc length and parametric function

    I'm having trouble with the following: The problem is to find the arc length of the following parametric function: x=(e^-t)(cos t), y=(e^-t)(sin t) from 0 to \pi I found that \frac{\partial y}{\partial t} = e^{-t}(\cos{t}-\sin{t}) , \frac{\partial x}{\partial t} =...
  20. A

    Arc Length Problem: Find Length from y=125 to y=216

    Hey, I need some help with an arc length question. It is: Find the length of the curve: x=3y^(4/3)-(3/32)y^(2/3) from y=125 to y= 216 So i know i need to use Arc Length=sqrt(1+(dx/dy)^2) but i can't seem to get the right answer. I have the derivative as 4y^(1/3)-(1/16)y^(-1/3). Squaring...
  21. U

    How Do You Calculate Arc Length and Volume of Rotated Solids in Calculus?

    i have 2 calculus questions that are due in the next half n hour and i have no idea how to even start them. I hope somoene can help me in time. Question1 Find the volume of the solid obtained if the plane region E bounded by the curve y=x^2 and y=x^3 between x=0 and x=1 is rotated about the...
  22. S

    Calc 3 Project: Solve Arc Length Problem with y = 1/c cosh(cx + b) + a

    Hey I got a project assigned for my Calc 3 class, and I was wondering what to do with the following: A hanging cable has the shape y = 1/c cosh(cx + b) + a for some constants a,b,c with c>0. Suppose the ends are at P(0,10) and P2(30,5). If the length of the cable is known to be 100...
  23. T

    Finding n for Arc Length of $\pi+e$ over Interval 0 to 6

    \int^{6}_{0} \sqrt{1-n^2x^2}dx=\pi+e I need to solve this for n. I believe there should only be one possible function of the form y=x^n that gives an arclength of \pi+e over the interval x=0 to x=6, and wish to find the value of n that such a function must have. Does anyone know how to do...
  24. N

    Find Arc Length Using Trapezoids

    Using trapezoids and N=4, find the length of the arc of the curve y=(1/3)x^3 from (0,0) to (1,1/3).
  25. D

    Solving Minimizing Arc Length: Euler-Lagrange Equations

    The problem I am working on asks me to find the curve on the surface z=x^(3/2) which minimizes arc length and connects the points (0,0,0) and (1,1,1). Here's what I did: Integral [sqrt(dx^2+dy^2+dz^2)] Integral [dx sqrt (1+(dy/dx)^2 +(dz/dx)^2] Integral [dx sqrt (1 + (dy/dx)^2 + 9x/4)]...
  26. S

    LaTeX Finding an arc length, and why isn't latex working for me?

    Finding an arc length I am attempting to find the arc length of y = cuberoot[x] between (1,1) and (8,2). I solved the integral from 1 to 2 of sqrt[1+(3y^2)^2]dy. I used a formula from a table of integrals in my text to solve this integral. The solution I get is 68.19. I can see that this...
  27. G

    Verifying Arc Length of Vector: <2e^t, e^-t, 2t>

    Hello, I was wondering if someone could check and see that i did this problem right. You need to find the arc length of the vector from t=0 to 1: r= <2e^t,e^-t,2t> So first i took the derivative and got velocity. v=<2e^t,-e^-t,2> Next i used the formula for arc length. arc...
  28. I

    Find the arc length of the given function

    This is my last homework problem and I feel that I almost have it solved. The problem is as followed: f(x) = \sqrt{4-x^2} Find the arc length of the given function from x=0 to x=2. I know that I am supposed to use this formula to solve for arclength: \int_{0}^{2} \sqrt{1 +...
  29. Cyrus

    Reparametrize the cure in terms of arc length instead of time

    Yikes, I am really starting to spam this place up! On the subject of curvature, it says that we can reparametrize the cure in terms of arc length instead of time. If we have time,t, and arc length s(t), we can write it as t=t(s). It seems to me that this is NOT true in general, if you...
  30. T

    Calculus 2: Finding Arc Length | Florida A&M Univ.

    The arc length... Hello all, this is my first post. I am a Computer Engineering Student at Florida A&M University taking Calculus 2 over the summer semester. Should finding the arc length be so extensive?? Are their shortcuts that I am missing? If you don't know the formula, the arc...
  31. J

    Weird arc length question

    I want to find two functions f(n,x) and g(n,x) such that f(n,x)sin(g(n,x)) always has a constant arc length over some interval [a,b]. Where n increases the amplitude but decreases the period. Any suggestions?
  32. C

    Calculating Arc Length in Multivariate Calculus

    here is the problem, and I can't seem to get very far, compute the length of r(t) = <3t, 4cost, 4sint> from t=0 to t=1 i know the formula is integral from 0 to 1 of length of r'(t) but I keep coming up with 5, and it doesn't seem right, can someone please confirm or deny this. Thanks
  33. O

    Arc Length In Polar Cordinates

    Hello, i am a high school student currently taking ap calculus. i am currently working on a research project on arc length in polar coordinates. through all of my research thus far the one thing that has eluded my grasp so far that is really frustrating is the applications in real life for...
  34. W

    Definition of Arc Length Function

    Hello, I am having trouble remembering some of the material required for my current calculus course so I am reviewing some of the previous material that I have forgotten. I am having trouble following the definition of The Arc Length Function as presented in James Stewart's "Calculus...
  35. T

    The Correct Arc Length Formula for Finding a Function F(x)

    Find a function F(x) whose arc length L(x) from (1,1/2) to (x,F(x)), x>1 is (1/2)x^2 + (1/4)Ln(x). First some short hand notation. Int[f(x),dx], means the indefinite integral of the function f(x). Int[f(x),dx,a,b], means the definite integral where a is the lower bound and b is the...
  36. D

    Parameterization of Arc Length Function

    I'm a little confused by the following in my textbook: Arc Length Function of a curve, 's', is defined by: s(t) = [inte]|r'(u)|du = [inte][squ]((dx/du)^2 + (dy/du)^2 + (dz/du)^2)du integrate both sides and you get ds/dt = |r'(t)|. Arc length is independent of the parameterization...
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