For a traveling wave
u(x,t) = u(x-ct)
How is the relation below hold?
u_{x}u_{xt}=-u_tu_{xx}
I don't understand why there is (-) sign .
Thanks in advance !
PS.
Here is the URL of the book I am having trouble with
https://www.amazon.com/dp/0198528523/?tag=pfamazon01-20...
I want to show that
if the energy is the integral :
E = \frac{1}{2} \int^{\infty}_{-\infty} u_{t}^2 \ dx
then the derivative of the energy with respect to time t is
\frac{dE}{dt} = - \int^{\infty}_{-\infty} u_{xt}^2 + f'(u) u_{t}^2 \ dx
What is the first step can you...
hi all.
I am very confusing there exists such a convergent number of this equation.
x[n] = 0.5(x[n-1]+x[n-2])
with the initial value x[0]=3, x[1]=5
if n goes infinity, x[n] may go to 13/3.
How can I approach this problem?
thanks.
Hi everyone.
I hardly remember the fomulas of summation of sequence.
I got this problem.
{\frac{1}{8}}\sum^{\infty}_{n=2}n({\frac{3}{4}})^{n-2}
The result is 2.5.
How can I solve this problem?
Thanks all. :)