Solving equations for Variable/Variable
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I have a simple question but i have not been able to find a way to achive this and was looking for some help. For example if I have the following code
syms A B C D E
eqn = (A*B*C)/E == D;
Is it there a function that will allow me to solve for C/D = ?. I have tried using solve but this provides a struct variable that solve the equation for c and D aka (solves for C= and D=).
Thanks
采纳的回答
No reason you cannot do this:
syms A B C D E
eqn = (A*B*C)/E == D;
syms CoverD
solve(subs(eqn,C,CoverD*D),CoverD)
3 个评论
Isaac Kambouris
2021-9-5
Just look. Take it apart.
syms A B C D E
eqn = (A*B*C)/E == D;
syms CoverD;
Effectively, I define the variable CoverD as C/D. So if we accept that
CoverD = C/D
then multiply by D. Can you solve for C? I hope so.
So what does this substitution do?
subs(eqn,C,CoverD*D)
It replaces C with the product CoverD*D. Now what happens to D in that expression? It effectively goes away, as long as D is not zero. And if D was zero, then what would be the meaning of the ratio C/D anyway? So we can assume D is never zero in this context.
The final solve should now be clear.
Isaac Kambouris
2021-9-6
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