# Question:about the use of collect

## Question:about the use of collect

Maple
when the expression is short, the 'collect' can works,but the expression is longer,it is different.for example: gg1 := collect(expression, z) tau[0]*D*a[1]*conjugate(q[2])^5*conjugate(ast)*b^3*A*zg^4/(1+b*x[2*ast]+c*y[ast])^3-tau[0]*D*a[1]*conjugate(q[2])^4*conjugate(ast)*b^2*A*zg^3/(1+b*x[2*ast]+c*y[ast])^2-tau[0]*D*a[1]*conjugate(q[2])^2*conjugate(ast)*C*zg^2*conjugate(q[3])/(1+b*x[2*ast]+c*y[ast])+tau[0]*D*a[1]*conjugate(q[2])^3*conjugate(ast)*b*A*zg^2/(1+b*x[2*ast]+c*y[ast])-tau[0]*D*a*conjugate(q[2])^3*conjugate(ast)*zg^2-tau[0]*D*a[1]*conjugate(q[2])^2*conjugate(ast)*C*zg^4*conjugate(q[3])^3*c^2/(1+b*x[2*ast]+c*y[ast])^3-tau[0]*D*a[1]*conjugate(q[2])^3*conjugate(ast)*b*A*zg^3*c*conjugate(q[3])/(1+b*x[2*ast]+c*y[ast])^2+2*tau[0]*D*a[1]*conjugate(q[2])^4*conjugate(ast)*b^2*A*zg^4*c*conjugate(q[3])/(1+b*x[2*ast]+c*y[ast])^3+tau[0]*D*a[1]*conjugate(q[2])^3*conjugate(ast)*C*zg^3*conjugate(q[3])*b/(1+b*x[2*ast]+c*y[ast])^2+tau[0]*D*a[1]*conjugate(q[2])^2*conjugate(ast)*C*zg^3*conjugate(q[3])^2*c/(1+b*x[2*ast]+c*y[ast])^2-tau[0]*D*a[1]*conjugate(q[2])^4*conjugate(ast)*C*zg^4*conjugate(q[3])*b^2/(1+b*x[2*ast]+c*y[ast])^3-2*tau[0]*D*a[1]*conjugate(q[2])^3*conjugate(ast)*C*zg^4*conjugate(q[3])^2*b*c/(1+b*x[2*ast]+c*y[ast])^3+tau[0]*D*a[1]*conjugate(q[2])^3*conjugate(ast)*b*A*zg^4*c^2*conjugate(q[3])^2/(1+b*x[2*ast]+c*y[ast])^3-tau[0]*D*a[1]*conjugate(q[2])^2*conjugate(ast)*c*B*conjugate(q[3])^2*zg^3*b/(1+b*x[2*ast]+c*y[ast])^2 ...... (....)*z^5+(....)*z^4+(...)*z^3+(....)*z^2+(....)*z^1+(....)*z^6 please pay attention to the order of power of z. thanks .
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