solve function errors/ faults

I am trying to solve a a 4-variable system of equations, however, I am getting the response:

Empty sym: 0-by-1

syms i1 i2 v1 v2

eqns = [-160 +10*i1+v1==0, 96==v2-12*i2,v2/v1==4, i1/i2 == 4 ];
s = solve(eqns,v1);

Any help would be much obliged.

Answer 1

[darova]

It's because of additional space

eqns = [-160 +10*i1+v1==0, 96==v2-12*i2,v2/v1==4, i1/i2 == 4 ];
size(eqns)

Try this solution

eqns = [-160+10*i1+v1==0, 96==v2-12*i2,v2/v1==4, i1/i2 == 4 ];

[Preston Glenn]

I still am getting the s = Empty sym: 0-by-1

syms i1 i2 v1 v2

eqns = [-160+10*i1+v1==0, 96==v2-12*i2,v2/v1==4, i1/i2 == 4 ];

s = solve(eqns,v1);
display(s);

[darova]

Try this

[Preston Glenn]

It worked thanks!

Answer 2

[Walter Roberson]

do not solve() a system of equations with multiple equations for a single variable. solve for as many variables as there are equations and select the appropriate output.

It does sometimes work to solve a system that includes inequalities if the number of equalities is the same as the number of variables being solved for.

[Preston Glenn]

This worked as well. Thank you!

[darova]

I did all the work myself. Why this question is accepted not mine?

[Walter Roberson]

darova, I provided a key solution and explanation before you provided the solution without explanation.

[darova]

Your solution is incomplete

[Preston Glenn]

They were both good answers, and I appreciate the help. I didn't know who's to accept so, I kinda hit accept both, and exited before seeing which was accepted. Thinking about it, Darova responded multiple times to help, so I switched to theirs.

[darova]

Thank you