# (Simple) How to solve basic equation

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A on 25 Nov 2014
Answered: Amutha S on 16 Dec 2020
Wondering if someone can help me find the error in this simple code. I'm trying to solve for N in terms of b and bt.
sym b bt N
k = 1/24;
l = (b + 0.5)/(6 + 12*b);
m = (b^2 + b/2)/(2 + 4*b);
q = ( (-k+l+m) + bt*(-4*k+3*l+2*m) )/ (1 + 2*bt);
eqn = -1/336 - l/24 + (6/5)*l^2 + 3*m/10 + 2*m*l + (2/3)*m^2 - q/6 - bt*q/6 + (3*l*q + 2*m*q)*(1+bt) == 1/N;
s = solve(eqn, N)
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### Accepted Answer

Star Strider on 25 Nov 2014
In R2014b, you have to replace ‘sym’ with ‘syms’. Otherwise, all you need to do is to add collect and simplify calls to get a simplified result:
s = solve(eqn, N)
s = simplify(collect(s),'steps',10)
produces:
s =
10080/((1260*bt + 1680)*b^2 + (420*bt + 1596)*b + 35*bt + 54)
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Star Strider on 26 Nov 2014
My pleasure!

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### More Answers (1)

Amutha S on 16 Dec 2020
sym b bt N
k = 1/24;
l = (b + 0.5)/(6 + 12*b);
m = (b^2 + b/2)/(2 + 4*b);
q = ( (-k+l+m) + bt*(-4*k+3*l+2*m) )/ (1 + 2*bt);
eqn = -1/336 - l/24 + (6/5)*l^2 + 3*m/10 + 2*m*l + (2/3)*m^2 - q/6 - bt*q/6 + (3*l*q + 2*m*q)*(1+bt) == 1/N;
s = solve(eqn, N)
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