Skip to main content

Solutions of selected exercises

  • Chapter
A Primer on PDEs

Part of the book series: UNITEXT ((UNITEXTMAT))

  • 3047 Accesses

Abstract

2.1. The problem is analyzed in Section 2.3.3. Its solution is given by (2.34):

$$ \rho \left(x,t\right)=\Big\{\begin{array}{l}\begin{array}{cc} {\rho}_m & \kern2.52em for\kern0.6em x\le -{v}_mt \end{array}\\ \begin{array}{cc} \frac{\rho_m}{2}\left(1-\frac{x}{v_mt}\right) & for-{v}_mt<x<{v}_mt, \end{array}\\ \begin{array}{cc} 0 & \kern3.12em for\kern0.5em x\ge {v}_mt \end{array}\end{array} $$

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 59.99
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD 79.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

Notes

  1. 1.

    The general solution for the linear first order equation \( \dot{y}=a(t)y(t)+\beta (t) \) is

    $$ y(t)={e}^{{\displaystyle \int a\; dt}}\left(C+{\displaystyle \int \beta {e}^{-{\displaystyle \int a\; dt}} dt}\right). $$
  2. 2.

    Appendix A.

  3. 3.

    Adiabatic extremes, considering the heat conduction in the bar.

  4. 4.

    It can be proved that ∫ L0 cos(k n x)cos(k m x)dx = 0 if mn. Furthermore, the functions \( {\varphi}_m(x)= \cos \left({k}_mx\right)\Big/\sqrt{a_m} \) are a base of the space L 2 (0, L) of square integrable functions (Chapter 7).

  5. 5.

    Appendx D.

  6. 6.

    See equation (10.2).

  7. 7.

    Appendix D.

  8. 8.

    It is a standard substitution for Euler equations.

  9. 9.

    The condition ψ′ > 0 ensures the local invertibility of the transformation.

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

Copyright information

© 2013 Springer-Verlag Italia

About this chapter

Cite this chapter

Salsa, S., Vegni, F.M.G., Zaretti, A., Zunino, P. (2013). Solutions of selected exercises. In: A Primer on PDEs. UNITEXT(). Springer, Milano. https://doi.org/10.1007/978-88-470-2862-3_10

Download citation

Publish with us

Policies and ethics