Solve Integral Inequality with cos(x): \int\sqrt{xcos(x)} dx 0..Pi/2

Click For Summary
SUMMARY

The integral inequality \(\int_0^{\frac{\pi}{2}}\sqrt{x\cos(x)} \, dx \leq \frac{\pi}{2}\sqrt{2}\) is established through the evaluation of the integral using properties of the cosine function. The discussion highlights the use of Maple software, which computes the integral involving elliptic functions, specifically EllipticK and EllipticE. The inequality is demonstrated by comparing \(\sqrt{x\cos(x)}\) to \(\sqrt{x}\), leading to a conclusive evaluation of the integral.

PREREQUISITES
  • Understanding of integral calculus, specifically definite integrals.
  • Familiarity with elliptic integrals, particularly EllipticK and EllipticE functions.
  • Proficiency in using Maple software for symbolic computation.
  • Knowledge of trigonometric functions and their properties.
NEXT STEPS
  • Study the properties and applications of EllipticK and EllipticE functions.
  • Learn how to perform symbolic integration using Maple 2023.
  • Explore techniques for evaluating definite integrals involving trigonometric functions.
  • Investigate the implications of integral inequalities in mathematical analysis.
USEFUL FOR

Mathematicians, students studying calculus, and anyone interested in advanced integral inequalities and elliptic functions.

phyguy321
Messages
45
Reaction score
0
Show that [tex]\int[/tex][tex]\sqrt{xcos(x)}[/tex] dx from 0..Pi/2 [tex]\leq[/tex] Pi/2 [tex]\sqrt{2}[/tex]


Having problems with the cos(x) part. Maple gives -sqrt(2)*EllipticK((1/2)*sqrt(2))+2*sqrt(2)*EllipticE((1/2)*sqrt(2)) for the integral of the cos part.

what are EllipticK and EllipticE and how are they evaluated?
so lost right now
 
Physics news on Phys.org
[tex]cosx\leq 1=>xcosx<x=>\sqrt{xcosx}\leq \sqrt{x}[/tex] now

[tex]\int_0^{\frac{\pi}{2}}\sqrt{xcosx}\leq \int_0^{\frac{\pi}{2}}\sqrt{x}=\frac{1}{2}\frac{2}{3}x^{\frac{3}{2}}|_0^{\frac{\pi}{2}}=\frac{1}{3}\frac{\pi}{2\sqrt{2}}<\frac{\pi}{2\sqrt{2}}[/tex]
 

Similar threads

  • · Replies 105 ·
4
Replies
105
Views
11K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 14 ·
Replies
14
Views
2K
Replies
3
Views
2K
  • · Replies 22 ·
Replies
22
Views
3K
Replies
4
Views
3K
  • · Replies 9 ·
Replies
9
Views
3K
Replies
9
Views
3K
Replies
3
Views
2K
  • · Replies 27 ·
Replies
27
Views
4K