Getting a empty sym 0x1 error when I run this code

syms dVf dVg P dP k Vg alpha Vf dTf beta m_f qdot wdot_s dTg Tg dhf
eq1 = dVf + dVg == 0; %constant volume
eq2 = (1/P)*dP + (1/Vg)*dVg == (1/Tg)*dTg; %ideal gas law
eq3 = (1/P)*dP + (k/Vg)*dVg == 0; %first law
eq4 = dVf == alpha*Vf*dTf - beta*Vf*dP; %liquid flow as a function of alpha and beta
eq5 = m_f*dhf == (qdot - wdot_s) + Vf*dP; %conservation of energy
[dP,dVg,dVf,dTf,dTg] = solve(eq1,eq2,eq3,eq4,eq5)

Answer 1

[Walter Roberson]

[dP,dVg,dVf,dTf,dTg] = solve([eq1,eq2,eq3,eq4,eq5],[dP,dVg,dVf,dTf,dTg])