# Homework Help: Wave equation diagram problem

1. Jan 7, 2015

### JI567

1. The problem statement, all variables and given/known data
The question is to sketch for values of t = 0, t =0.25, t = 0.5, t=1 and t = 1.25 for the wave equation

Ytt = Yxx in the infinite domain with initial conditions

y(x,0) = f(x) =
\begin{cases}
1 & \text{if } 0 ≤ x ≤ 1 \\
& 0 (otherwise)
\end{cases}

Yt(x,0) = 0

2. Relevant equations
Y(x,t) = a(x,t) + b(x,t)

where a(x,t) = $\frac {1} {2} \$ f(x+t)
and b(x,t) = $\frac {1} {2} \$ f(x-t)

3. The attempt at a solution
These are the sketches I obtained for those times and they are not to exactly measured to the points as I did them in paint. Can someone please tell me if the sketches are correct for this question!

for t =0

for t= 0.25

Attaching the remaining ones in the post below as you can't attach more than 6 in one post.

File size:
2.3 KB
Views:
167
File size:
19 KB
Views:
136
2. Jan 7, 2015

### JI567

for t = 0.5 s

for t = 1 s

3. Jan 7, 2015

### BvU

Hi JI,

As you may know, PF has great difficulty handing out approval stamps: it could create big problems with teachers, exam committees and what have you. PF homework is meant to help folks when they get stuck; with hints, questions and advice. My personal opinion is you don't need any of those :)

and ;)

4. Jan 7, 2015

### JI567

Look man can you be more clear? I don't understand what are you talking about. All I asked is if my sketches are correct or not, I am not asking you to do my homework for me.

5. Jan 7, 2015

### BvU

Yes I can be more clear: I think what you did is excellent -- but you can't derive any rights from my statements.

My post #3 tries to express some reluctance about the "Is this correct" questions.

6. Jan 7, 2015

### JI567

Cheers mate! I just realized I missed out t= 1.25 s for this question

Can you see the sketches for t = 1.25 s are excellent as well

7. Jan 7, 2015

### BvU

As I said: you're so good you don't need assistance here :)

You do have me wondering what's the reason you ask for confirmation: you clearly understand everything that's going on, so why this possible doubt ?

8. Jan 7, 2015

### JI567

Cheers! I just want to be 100% sure that my works are correct so that I get full marks....so even if I understand everything I want to confirm with people who has more knowledge than me.