Can I use the symbolic math tool box to solve a series of expressions symbolically with respect to specific terms?

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I would like to solve the following system of symbolic expressions for symbol A with respect to symbols n, K, I, P and D. I have tried using the "solve symbolic equation" task in the live script but I'm unsure how to specificy which symbols I want in the final expression. Below is the code I have thus far:
syms B E A X n K P I D V W
eqn1 = (B*E)/(A^(1/2)*X^n) == K
eqn2 = D + B == E
eqn3 = X + n*B == P
eqn4 = A + B/2 == I
eqn5 = 0.05 == I
eqn6 = (2*I-2*A)/(A^(1/2)*(P-n*(2*I-2*A))^n) == K
eqn7 = (P/n - (E*V)/(n-n*V))/(A^(1/2)*((E*V)/(1-V))^n) == K
eqn8 = (P-n*B)/(D+B+P-n*B) == V
eqn9 = E/(E+X) == W
eqn10 = X/(E+X) == V
eqn11 = V+W == 1
eqn12 = n == 2
eqns = [eqn1 eqn2 eqn3 eqn4 eqn5 eqn6 eqn7 eqn8 eqn9 eqn10 eqn11]
S = solve(eqns,[A])

Answers (1)

Walter Roberson
Walter Roberson on 29 Nov 2021
You must solve() for as many variables as the rank of the system.
You have 12 equations in 11 variables. There might not be a solution at all.
If you want to solve in terms of 5 variables then you can solve no more than 12-5=7 of the equations.
I recommend against solving 0.05==I or n==2. Just substitute those into the equations. Well except for the fact that you want to solve in terms of symbol I even though you know its exact value, so maybe leave that equation out.

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