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## coeff help

Maple
How do i find the coeff? It is not working! > restart: > alias(epsilon=ep); epsilon > eqn := ep*x^4 - 3*x^2 -2*x + 1; 4 2 eqn := epsilon x - 3 x - 2 x + 1 > eqn1 := simplify(subs(x=ep^(n)*y,eqn)/epsilon^(1+4*n)); 4 (-1 - 2 n) 2 (-1 - 3 n) (-1 - 4 n) eqn1 := y - 3 epsilon y - 2 epsilon y + epsilon > asym1 := sum(y[n]*ep^(n), n=0..3); 2 3 asym1 := y[0] + y[1] epsilon + y[2] epsilon + y[3] epsilon > meth1 := subs(n=-1/2,y=asym1,eqn1); 4 / 2 3\ meth1 := \y[0] + y[1] epsilon + y[2] epsilon + y[3] epsilon / 2 / 2 3\ - 3 \y[0] + y[1] epsilon + y[2] epsilon + y[3] epsilon / (1/2) / 2 3\ - 2 epsilon \y[0] + y[1] epsilon + y[2] epsilon + y[3] epsilon / + epsilon > step21 := collect(expand(meth1,ep=0),ep); 4 12 11 3 step21 := y[3] epsilon + 4 y[2] epsilon y[3] / 3 2 2\ 10 + \4 y[1] y[3] + 6 y[2] y[3] / epsilon / 3 2 3\ 9 + \4 y[2] y[3] + 12 y[1] y[2] y[3] + 4 y[0] y[3] / epsilon / 2 2 2 4 2 \ + \6 y[1] y[3] + 12 y[0] y[2] y[3] + y[2] + 12 y[1] y[2] y[3]/ 8 epsilon / 2 2 3 + \12 y[1] y[2] y[3] + 12 y[0] y[1] y[3] + 4 y[1] y[2] 2 \ 7 + 12 y[0] y[2] y[3]/ epsilon / 3 3 2 + \24 y[0] y[1] y[2] y[3] + 4 y[1] y[3] + 4 y[0] y[2] - 3 y[3] 2 2 2 2\ 6 + 6 y[1] y[2] + 6 y[0] y[3] / epsilon / 2 2 3 + \12 y[0] y[1] y[3] + 12 y[0] y[1] y[2] - 6 y[2] y[3] + 4 y[1] y[2] 2 \ 5 + 12 y[0] y[2] y[3]/ epsilon / 4 2 2 2 2 + \y[1] - 6 y[1] y[3] + 12 y[0] y[1] y[2] + 6 y[0] y[2] - 3 y[2] 2 \ 4 (7/2) + 12 y[0] y[1] y[3]/ epsilon - 2 epsilon y[3] / 3 2 + \4 y[0] y[1] - 6 y[1] y[2] - 6 y[0] y[3] + 12 y[0] y[1] y[2] 3 \ 3 (5/2) + 4 y[0] y[3]/ epsilon - 2 epsilon y[2] / 3 2 2 2 \ 2 + \4 y[0] y[2] - 3 y[1] + 6 y[0] y[1] - 6 y[0] y[2]/ epsilon (3/2) / 3 \ - 2 epsilon y[1] + \1 - 6 y[0] y[1] + 4 y[0] y[1]/ epsilon (1/2) 2 4 - 2 epsilon y[0] - 3 y[0] + y[0] > zeroth1 := subs(ep=0,step21); 2 4 zeroth1 := -3 y[0] + y[0] > soln01 := [solve(zeroth1=0,y[0])]; [ (1/2) (1/2)] soln01 := [0, 0, 3 , -3 ] > coeff(step21,epsilon,2); Error, unable to compute coeff

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