Trinh @ Bath

Trace:

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision 		Previous revision
vpde_errata [2020/04/04 21:29]
trinh 		vpde_errata [2020/04/30 20:43] (current)
trinh
Line 21: Line 21:
   * PS3: Index notation needs to be removed from the main solutions in 19-20' delivery since the topic has been moved to the Appendix. Students are still free to use the technique if they learn it (as noted in lectures).    * PS3: Index notation needs to be removed from the main solutions in 19-20' delivery since the topic has been moved to the Appendix. Students are still free to use the technique if they learn it (as noted in lectures). 
   * PS4 Q4 $dx$ and $dy$ transposed    * PS4 Q4 $dx$ and $dy$ transposed 
-  * PS6 Q1. The function $\sin(x)\exp(-\cos(x^2))$ is indeed not periodic but not for the reasons stated in the solutions. The point here is that $\cos(x^2)$ is not a periodic function. You can verify this either by checking whether it's possible that $(x+L)^2 = x^2 + n*\pi$ independent of $x$, or simply by plotting the $\cos($x^2)$ and observing its behaviour, particularly near the origin.+  * PS6 Q1. The function $\sin(x)\exp(-\cos(x^2))$ is indeed not periodic but not for the reasons stated in the solutions. The point here is that $\cos(x^2)$ is not a periodic function. You can verify this either by checking whether it's possible that $(x+L)^2 = x^2 + n\pi$ independent of $x$, or simply by plotting the $\cos($x^2)$ and observing its behaviour, particularly near the origin. 
 +  * **PS9 Q2:** There is a missing factor of $p$ on the bottom here. See Lecture 29. 
 +  * **PS9 Q4:** Looks like axes were doubled here. //(Courtesy RA, HC)// 
 +  * **PS10 Q2:** Looks like there are a few $\kappa$s missing on the right hand side (I count three); **Q3** In the redefinition of the energy (above "So now you are back to...") there is a extra d/dt that should not be there.
  
 ==== Lectures ==== ==== Lectures ====
   * Correction to {{ :ma20223:ma20223-Week6.pdf |lectures 16}} when I wrote "Is $\exp(\cos x)$ periodic? (No)". Oops. It is periodic. Note that $\exp(f(x+L)) = \exp(f(x))$. A similar gaff appears in the solutions of PS6.    * Correction to {{ :ma20223:ma20223-Week6.pdf |lectures 16}} when I wrote "Is $\exp(\cos x)$ periodic? (No)". Oops. It is periodic. Note that $\exp(f(x+L)) = \exp(f(x))$. A similar gaff appears in the solutions of PS6. 
 +
 +==== Past exams ====
 +  * 2017-18 exam Q4d. The index should start from $n = 1$ once the $2n+1$ shift is done.
Last modified: 2020/04/04 21:29