- #1
Gekko
- 71
- 0
du/dt = d2u/dx2
u(x,t) = (t^a) * (g(e)) where e = x/sqrt(t) and a is a constant
Show that
integral from -inf to inf [ u(x,t) ] dx = integral from -inf to inf [ (t^a) * g(e) ] dx
is independent of t only if a=-0.5
My attempt was to diff both sides by t (sorry not x) giving
integral from -inf to inf [d2u/dx2 ] dx = integral from -inf to inf [at^(a-1) g(e) + t^a dg(g)/dt ] dx
Not sure if this is correct and can't see where to go from here...any help most appreciated. Thanks
u(x,t) = (t^a) * (g(e)) where e = x/sqrt(t) and a is a constant
Show that
integral from -inf to inf [ u(x,t) ] dx = integral from -inf to inf [ (t^a) * g(e) ] dx
is independent of t only if a=-0.5
My attempt was to diff both sides by t (sorry not x) giving
integral from -inf to inf [d2u/dx2 ] dx = integral from -inf to inf [at^(a-1) g(e) + t^a dg(g)/dt ] dx
Not sure if this is correct and can't see where to go from here...any help most appreciated. Thanks
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