Question: Question on solve technique

In the attached, I had to find the required coefficient. Now this has a relatively straight forward set of equation (which apparently form a closed group), so it was easy enough tee see what to do. In a more complicated situation that may be very difficult to see. I was a wondering is there is a better approach to use here?
 

restart

Prove/show the coefficient of c[0] in c[1]^11 is 1/12*(1-1/5^10)NULL

eq1 := c[1]^2 = (1/5)*c[0]+(2/5)*c[1]+(2/5)*c[2]

c[1]^2 = (1/5)*c[0]+(2/5)*c[1]+(2/5)*c[2]

(1)

eq2 := c[1]*c[2] = (2/5)*c[1]+(2/5)*c[2]+(1/5)*c[3]

c[1]*c[2] = (2/5)*c[1]+(2/5)*c[2]+(1/5)*c[3]

(2)

eq3 := c[1]*c[3] = c[2]

c[1]*c[3] = c[2]

(3)

eq4 := c[2]*c[3] = c[1]

c[2]*c[3] = c[1]

(4)

eq5 := c[2]^2 = (1/5)*c[0]+(2/5)*c[1]+(2/5)*c[2]

c[2]^2 = (1/5)*c[0]+(2/5)*c[1]+(2/5)*c[2]

(5)

eq6 := c[3]^2 = c[0]

c[3]^2 = c[0]

(6)

 

expand(eq1^5)

c[1]^10 = (1/3125)*c[0]^5+(32/3125)*c[1]^5+(32/3125)*c[2]^5+(16/625)*c[0]*c[1]^4+(16/625)*c[0]*c[2]^4+(2/625)*c[0]^4*c[1]+(2/625)*c[0]^4*c[2]+(8/625)*c[0]^3*c[1]^2+(8/625)*c[0]^3*c[2]^2+(16/625)*c[0]^2*c[1]^3+(16/625)*c[0]^2*c[2]^3+(32/625)*c[1]*c[2]^4+(32/625)*c[1]^4*c[2]+(64/625)*c[1]^3*c[2]^2+(64/625)*c[1]^2*c[2]^3+(64/625)*c[0]*c[1]^3*c[2]+(96/625)*c[0]*c[1]^2*c[2]^2+(64/625)*c[0]*c[1]*c[2]^3+(16/625)*c[0]^3*c[1]*c[2]+(48/625)*c[0]^2*c[1]^2*c[2]+(48/625)*c[0]^2*c[1]*c[2]^2

(7)

C111 := lhs(%)*c[1] = expand(rhs(%)*c[2]*c[3])

c[1]^11 = (1/3125)*c[2]*c[3]*c[0]^5+(32/3125)*c[2]*c[3]*c[1]^5+(32/3125)*c[2]^6*c[3]+(16/625)*c[2]*c[3]*c[0]*c[1]^4+(16/625)*c[2]^5*c[3]*c[0]+(2/625)*c[2]*c[3]*c[0]^4*c[1]+(2/625)*c[2]^2*c[3]*c[0]^4+(8/625)*c[2]*c[3]*c[0]^3*c[1]^2+(8/625)*c[2]^3*c[3]*c[0]^3+(16/625)*c[2]*c[3]*c[0]^2*c[1]^3+(16/625)*c[2]^4*c[3]*c[0]^2+(32/625)*c[2]^5*c[3]*c[1]+(32/625)*c[2]^2*c[3]*c[1]^4+(64/625)*c[2]^3*c[3]*c[1]^3+(64/625)*c[2]^4*c[3]*c[1]^2+(64/625)*c[2]^2*c[3]*c[0]*c[1]^3+(96/625)*c[2]^3*c[3]*c[0]*c[1]^2+(64/625)*c[2]^4*c[3]*c[0]*c[1]+(16/625)*c[2]^2*c[3]*c[0]^3*c[1]+(48/625)*c[2]^2*c[3]*c[0]^2*c[1]^2+(48/625)*c[2]^3*c[3]*c[0]^2*c[1]

(8)

c[1]^11 = simplify(rhs(C111), [eq2, eq3, eq4, eq5, eq6])

c[1]^11 = (1/9765625)*(4070573*c[3]+4067448)*c[2]+(813802/9765625)*c[0]+(813802/9765625)*c[3]

(9)

coeff(rhs(%), c[0], 1)

813802/9765625

(10)

eval(1/12*(1-1/5^10))

813802/9765625

(11)

NULL


 

Download Graphs_steps.mw

Please Wait...