What is the Length of a Curve with a Cubic Equation?

Then it will be easy to integrate.In summary, the conversation involved finding the length of a curve y = x^3/a^2 + a^2/12x between a and a/2 and applying the formula Length L = integrate (1+ (dy/dx)^2)^0.5. The attempt at a solution led to integrating (9x^4/a^2 + 1/2 + a^4/144x^4)^0.5, but the user was unable to simplify it. It was suggested to re-check the arithmetic for the first term and it was mentioned that the quantity under the radical is a perfect square, making it easy to integrate.
  • #1
applestrudle
64
0

Homework Statement



Find the length of the curve y = x^3/a^2 + a^2/12x

between a and a/2


Homework Equations



Length L = integrate (1+ dy/dx)^2)^0.5

The Attempt at a Solution



I got to

integrate (9x^4/a^2 + 1/2 + a^4/144x^4)^0.5

but I can't simplify it
 
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  • #2
applestrudle said:

Homework Statement



Find the length of the curve y = x^3/a^2 + a^2/12x

Is that last term supposed to be ##\frac {a^2}{12x}## or ##\frac{a^2x}{12}##?
between a and a/2


Homework Equations



Length L = integrate (1+ dy/dx)^2)^0.5

The Attempt at a Solution



I got to

integrate (9x^4/a^2 + 1/2 + a^4/144x^4)^0.5

but I can't simplify it

Did you leave out the ##1##? It would help if you showed your work.
 
  • #3
LCKurtz said:
Is that last term supposed to be ##\frac {a^2}{12x}## or ##\frac{a^2x}{12}##?Did you leave out the ##1##? It would help if you showed your work.

the last term is a^2 / (12x) x in the denominator.

yeah i left out the 1, that was a typo.

L = intergrate (1+ (dy/dx)^2)^0.5

thanks
 
  • #4
applestrudle said:
integrate (9x^4/a^2 + 1/2 + a^4/144x^4)^0.5

Re-check your arithmetic for that first term and you should be able to work out that the quantity under the radical is a perfect square.
 

1. What is a length of curve integral?

A length of curve integral is a mathematical concept used to find the length of a curve on a graph. It involves breaking the curve into small segments and calculating the length of each segment using the Pythagorean theorem. The total length is then found by summing up all the segments.

2. How is a length of curve integral calculated?

To calculate a length of curve integral, you first need to determine the equation of the curve. Then, you divide the curve into small segments and use the Pythagorean theorem to find the length of each segment. Finally, you add up all the segments to get the total length.

3. What is the significance of a length of curve integral?

A length of curve integral is important in various fields of science and engineering, such as physics, calculus, and geometry. It allows for the accurate measurement of curves and is used in the design and analysis of structures and systems.

4. Can a length of curve integral be negative?

No, a length of curve integral cannot be negative. The length of a curve is always a positive value, as it represents the distance between two points on the curve.

5. Are there any real-world applications of a length of curve integral?

Yes, there are many real-world applications of a length of curve integral. It is used in fields like architecture, engineering, and physics to calculate the length of curved surfaces, such as bridges, roads, and pipes. It is also used in computer graphics to create smooth and realistic curves in 3D animations and designs.

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