一个关于提取系数的问题

wilw8

请问用maple如何提取下面式子里f(x)^i*g(x)^j的系数？(coeffs命令会出现错误：Error, invalid input: coeffs expects its 3rd argument, t, to be of type name, but received [f(xi), g(xi)])
omega*B[2]*f(x)^9+omega*B[3]*f(x)^10*g(x)^4+omega*B[1]*f(x)^8-rho*B[2]*f(x)^11*b[2]*g(x)-6*a^2*alpha*B[1]*f(x)^10-12*a^2*alpha*B[2]*f(x)^11

TBE_Legend

请问用maple如何提取下面式子里f(x)^i*g(x)^j的系数？(coeffs命令会出现错误：Error, invalid input: coeffs expects its 3rd argument, t, to be of type name, but received [f(xi), g(xi)])
omega*B[2]*f(x)^9+o ...
wilw8 发表于 2009-10-30 17:49

试试这个行否？

1. 
   
2. restart;
   
3. s := omega*B[2]*f(x)^9+omega*B[3]*f(x)^10*g(x)^4+omega*B[1]*f(x)^8-rho*B[2]*f(x)^11*b[2]*g(x)-6*a^2*alpha*B[1]*f(x)^10-12*a^2*alpha*B[2]*f
   
4. (x)^11;
   
5. s1:=expand(algsubs(f(x)*g(x)=F,s));
   
6. coeffs(s1, F, 't');
   
7. t;
   

复制代码

maplelab

wilw8

谢谢楼上二位的热心解答！！！问题解决了:victory: