Math Practice: Periodic Functions

[scariari]

I'm doing a practice exam for a math test on thursday, wondering if anyone could help figure out how to get from one step to the next. i don't think that the background info is necessary for these two steps.

the file is attached (Adobe acrobat).

what i am wondering about is the answer under (2b).
If the solution for finding (del)u(x,y) were lettered a through d (4 steps, i am wondering how the professer got from b to c.

of course i have emailed him as well.

 

[nbo10]

Look in the last line of the 2b) paragraph.
$\Delta \frac{16}{\pi^4 kl(k^2+l^2)}sin(k \pi x)sin(l \pi y) =$
$\frac{16}{\pi^4 kl(k^2+l^2)}(-\pi^2 (k^2 + l^2)sin(k\pi x)sin(l\pi y)) <br />$

JMD

 

[M98Ranger]

Hi there,

I can definitely help you with understanding the steps for finding (del)u(x,y) in the practice exam. However, without the background information or the attached file, it is difficult for me to provide specific guidance. Can you please provide more context or share the file so I can see the steps and provide a clear explanation?

In general, the process for solving periodic functions involves identifying the period, amplitude, and phase shift, and then using these values to create a graph or an equation. From there, you can use calculus techniques to find the derivative, which is (del)u(x,y) in this case.

I recommend reaching out to your professor for clarification on the steps or providing more information for me to assist you further. Good luck on your test on Thursday!