Solution 1 to problem l2o57


Expressions | Parameters | Relevance | Back to problem l2o57

Expressions

The solution is given through the following expressions:

b45=2*b43


b44=b43


      2
     ---*a2*b43
      3
b42=------------
        a11


     2*a2*b43
b41=----------
       a11


      2
     ---*a2*b43
      3
b40=------------
        a11


      2
     ---*a2*b43
      3
b39=------------
        a11


b38=0


b37=0


      5
     ---*a11*b43
      3
b36=-------------
         a7


     5*a11*b43
b35=-----------
        a7


b34=0


b33=0


      5
     ---*a2*b43
      3
b32=------------
         a7


      10
     ----*a2*b43
      3
b31=-------------
         a7


      20
     ----*a2*b43
      3
b30=-------------
         a7


      10
     ----*a2*b43
      3
b29=-------------
         a7


b28=0


b27=0


b26=0


b25=0


      2    2
     ---*a2 *b43
      3
b24=-------------
       a11*a7


      2    2
     ---*a2 *b43
      3
b23=-------------
       a11*a7


b22=0


     a7*b43
b21=--------
      a11


b20=5*b43


b19=5*b43


      10
     ----*a2*b43
      3
b18=-------------
         a11


     10*a2*b43
b17=-----------
        a11


      20
     ----*a2*b43
      3
b16=-------------
         a11


      20
     ----*a2*b43
      3
b15=-------------
         a11


      20
     ----*a2*b43
      3
b14=-------------
         a11


      5
     ---*a2*b43
      3
b13=------------
        a11


      2    2
     ---*a2 *b43
      3
b12=-------------
           2
        a11


      10    2
     ----*a2 *b43
      3
b11=--------------
            2
         a11


      20    2
     ----*a2 *b43
      3
b10=--------------
            2
         a11


     35
    ----*a11*b43
     3
b9=--------------
         a7


     35
    ----*a2*b43
     3
b8=-------------
        a7


     140
    -----*a2*b43
      3
b7=--------------
         a7


     35
    ----*a2*b43
     3
b6=-------------
        a7


     70    2
    ----*a2 *b43
     3
b5=--------------
       a11*a7


         2
    14*a2 *b43
b4=------------
      a11*a7


     14    2
    ----*a2 *b43
     3
b3=--------------
       a11*a7


     2    3
    ---*a2 *b43
     3
b2=-------------
         2
      a11 *a7


     a11*a7
a18=--------
       a2


      1
     ---*a11*a7
      2
a17=------------
         a2


      3     2
     ---*a11
      2
a16=----------
        a2


          2
     3*a11
a15=--------
       a2


a14=0


a13=0


a12=a11


a10=0


    3*a11*a7
a9=----------
       a2


     3
    ---*a11*a7
     2
a8=------------
        a2


a6=3*a7


     15     2
    ----*a11
     2
a5=-----------
       a2


a4=10*a11


a3=5*a11


Parameters

Apart from the condition that they must not vanish to give a non-trivial solution and a non-singular solution with non-vanishing denominators, the following parameters are free:
 b43,a7,a11,a2

Relevance for the application:

The solution given above tells us that the system {u_s, v_s} is a higher order symmetry for the lower order system {u_t,v_t} where u=u(t,x) is a scalar function, v=v(t,x) is a vector function of arbitrary dimension and f(..,..) is the scalar product between two such vectors:
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\

               2                                        3
df(u,t)=(u  *a2  + 5*u  *a11*a2*u + 10*u  *u *a11*a2 + ---*u *f(v,v)*a11*a7
          5x          3x                2x  x           2   x

             15        2  2
          + ----*u *a11 *u  + 3*f(v ,v  )*a2*a7 + f(v,v  )*a2*a7
             2    x                x  2x               3x

          + 3*f(v,v )*a11*a7*u)/a2
                   x

          2        3        14            2                         2
df(u,s)=(---*u  *a2 *b43 + ----*u  *a11*a2 *b43*u + 14*u  *u *a11*a2 *b43
          3   7x            3    5x                     4x  x

             70                2        5
          + ----*u  *u  *a11*a2 *b43 + ---*u  *f(v,v)*a11*a2*a7*b43
             3    3x  2x                3   3x

             35         2         2    140            2
          + ----*u  *a11 *a2*b43*u  + -----*u  *u *a11 *a2*b43*u
             3    3x                    3    2x  x

             20                               35    3    2
          + ----*u  *f(v,v )*a11*a2*a7*b43 + ----*u  *a11 *a2*b43
             3    2x      x                   3    x

             20                               20
          + ----*u *f(v ,v )*a11*a2*a7*b43 + ----*u *f(v,v  )*a11*a2*a7*b43
             3    x    x  x                   3    x      2x

                           2             35        3      3
          + 5*u *f(v,v)*a11 *a7*b43*u + ----*u *a11 *b43*u
               x                         3    x

             20               2           10              2
          + ----*f(v  ,v  )*a2 *a7*b43 + ----*f(v ,v  )*a2 *a7*b43
             3      2x  3x                3      x  4x

                                            2             2
          + 10*f(v ,v  )*a11*a2*a7*b43*u + ---*f(v,v  )*a2 *a7*b43
                  x  2x                     3       5x

             10                                                  2
          + ----*f(v,v  )*a11*a2*a7*b43*u + f(v,v )*f(v,v)*a11*a7 *b43
             3        3x                         x

                         2         2      2
          + 5*f(v,v )*a11 *a7*b43*u )/(a11 *a7)
                   x

                                                2        1
df(v,t)=(u  *a11*a2*v + u  *v *a11*a2 + 3*u *a11 *u*v + ---*v *f(v,v)*a11*a7
          3x             2x  x             x             2   x

             3        2  2
          + ---*v *a11 *u  + f(v,v )*a11*a7*v)/a2
             2   x                x

          2        2          2           2        10
df(v,s)=(---*u  *a2 *b43*v + ---*u  *v *a2 *b43 + ----*u  *a11*a2*b43*u*v
          3   5x              3   4x  x            3    3x

             20                         10
          + ----*u  *u *a11*a2*b43*v + ----*u  *v *a11*a2*b43*u
             3    2x  x                 3    2x  x

             5    2                                                  2      2
          + ---*u  *v *a11*a2*b43 + u *f(v,v)*a11*a7*b43*v + 5*u *a11 *b43*u *v
             3   x   x               x                          x

             2                           2
          + ---*v *f(v ,v )*a2*a7*b43 + ---*v *f(v,v  )*a2*a7*b43
             3   x    x  x               3   x      2x

                                      5        2      3
          + v *f(v,v)*a11*a7*b43*u + ---*v *a11 *b43*u
             x                        3   x

                                       2
          + 2*f(v ,v  )*a2*a7*b43*v + ---*f(v,v  )*a2*a7*b43*v
                 x  2x                 3       3x

          + 2*f(v,v )*a11*a7*b43*u*v)/(a11*a7)
                   x

df(u,t)=(df(u,x,5)*a2**2 + 5*df(u,x,3)*a11*a2*u + 10*df(u,x,2)*df(u,x)*a11*a2 + 
3/2*df(u,x)*f(v,v)*a11*a7 + 15/2*df(u,x)*a11**2*u**2 + 3*f(df(v,x),df(v,x,2))*a2
*a7 + f(v,df(v,x,3))*a2*a7 + 3*f(v,df(v,x))*a11*a7*u)/a2$

df(u,s)=(2/3*df(u,x,7)*a2**3*b43 + 14/3*df(u,x,5)*a11*a2**2*b43*u + 14*df(u,x,4)
*df(u,x)*a11*a2**2*b43 + 70/3*df(u,x,3)*df(u,x,2)*a11*a2**2*b43 + 5/3*df(u,x,3)*
f(v,v)*a11*a2*a7*b43 + 35/3*df(u,x,3)*a11**2*a2*b43*u**2 + 140/3*df(u,x,2)*df(u,
x)*a11**2*a2*b43*u + 20/3*df(u,x,2)*f(v,df(v,x))*a11*a2*a7*b43 + 35/3*df(u,x)**3
*a11**2*a2*b43 + 20/3*df(u,x)*f(df(v,x),df(v,x))*a11*a2*a7*b43 + 20/3*df(u,x)*f(
v,df(v,x,2))*a11*a2*a7*b43 + 5*df(u,x)*f(v,v)*a11**2*a7*b43*u + 35/3*df(u,x)*a11
**3*b43*u**3 + 20/3*f(df(v,x,2),df(v,x,3))*a2**2*a7*b43 + 10/3*f(df(v,x),df(v,x,
4))*a2**2*a7*b43 + 10*f(df(v,x),df(v,x,2))*a11*a2*a7*b43*u + 2/3*f(v,df(v,x,5))*
a2**2*a7*b43 + 10/3*f(v,df(v,x,3))*a11*a2*a7*b43*u + f(v,df(v,x))*f(v,v)*a11*a7
**2*b43 + 5*f(v,df(v,x))*a11**2*a7*b43*u**2)/(a11**2*a7)$

df(v,t)=(df(u,x,3)*a11*a2*v + df(u,x,2)*df(v,x)*a11*a2 + 3*df(u,x)*a11**2*u*v + 
1/2*df(v,x)*f(v,v)*a11*a7 + 3/2*df(v,x)*a11**2*u**2 + f(v,df(v,x))*a11*a7*v)/a2$

df(v,s)=(2/3*df(u,x,5)*a2**2*b43*v + 2/3*df(u,x,4)*df(v,x)*a2**2*b43 + 10/3*df(u
,x,3)*a11*a2*b43*u*v + 20/3*df(u,x,2)*df(u,x)*a11*a2*b43*v + 10/3*df(u,x,2)*df(v
,x)*a11*a2*b43*u + 5/3*df(u,x)**2*df(v,x)*a11*a2*b43 + df(u,x)*f(v,v)*a11*a7*b43
*v + 5*df(u,x)*a11**2*b43*u**2*v + 2/3*df(v,x)*f(df(v,x),df(v,x))*a2*a7*b43 + 2/
3*df(v,x)*f(v,df(v,x,2))*a2*a7*b43 + df(v,x)*f(v,v)*a11*a7*b43*u + 5/3*df(v,x)*
a11**2*b43*u**3 + 2*f(df(v,x),df(v,x,2))*a2*a7*b43*v + 2/3*f(v,df(v,x,3))*a2*a7*
b43*v + 2*f(v,df(v,x))*a11*a7*b43*u*v)/(a11*a7)$