MHB Who can give me a hint of how to calculate this integral,Thanks

  • Thread starter Thread starter zhaojx84
  • Start date Start date
Click For Summary
The integral discussed is $$\int_{0}^{\frac{-a}{2}+\frac{\sqrt{392-{a}^{2}}}{2}} {y}^{2}\arcsin\left({\frac{a+y}{\sqrt{196-{y}^{2}}}}\right)\,dy$$, which lacks an explicit evaluation but has interesting numerical solutions. Users suggest using GNU Octave or PTC Mathcad Prime 3.0 for calculations and visualizations. The GNU Octave code provided allows for numerical integration and plotting of the function. There is curiosity about the underlying formula for the curve represented by the integral. Overall, the discussion emphasizes numerical methods and software tools for evaluating complex integrals.
zhaojx84
Messages
8
Reaction score
0
View attachment 7756
$$\int_{0}^{\frac{-a}{2}+\frac{\sqrt{392-{a}^{2}}}{2}} {y}^{2}\arcsin\left({\frac{a+y}{\sqrt{196-{y}^{2}}}}\right)\,dy$$
 

Attachments

  • 新建位图图像2.jpg
    新建位图图像2.jpg
    8.3 KB · Views: 129
Physics news on Phys.org
I'm not seeing an explicit evaluation, but I found the numerical solutions fascinating:View attachment 7762
 

Attachments

  • arcsine.jpg
    arcsine.jpg
    15.3 KB · Views: 141
tkhunny said:
I'm not seeing an explicit evaluation, but I found the numerical solutions fascinating:

Thanks very much. Could you tell me which software did you use to express this curve? Is there a formula for this curve. Thanks again for your help.
 
zhaojx84 said:
Thanks very much. Could you tell me which software did you use to express this curve? Is there a formula for this curve. Thanks again for your help.

Hi zhaojx84, welcome to MHB! (Wave)

In GNU Octave, the free version of MatLab, we can do:
Code:
f = @(a, y) y^2 * asin((a + y) / (sqrt(196 - y^2)));
g = @(a) quad(@(y) f(a, y), 0, (-a / 2 + (sqrt(392 - a^2)) / 2));
x = -11:0.2:14;
y = arrayfun(g, x);
plot(x, y);

In Octave Online, we can quickly see what it does.

View attachment 7768
 

Attachments

  • Octave_online_demo.png
    Octave_online_demo.png
    33.2 KB · Views: 114
zhaojx84 said:
Thanks very much. Could you tell me which software did you use to express this curve? Is there a formula for this curve. Thanks again for your help.
I used PTC Mathcad Prime 3.0

It required pretty much what you see. Just type in what you want. The algebraic interpretation is provided.
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
1K
Replies
4
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 12 ·
Replies
12
Views
2K
Replies
3
Views
3K
  • · Replies 6 ·
Replies
6
Views
2K
Replies
2
Views
3K