Problem solving a system of equations using SymPy


#1

I am trying to solve a system of equations:

using SymPy
@syms F_t delta F_a beta_c F_tp F_ap g_p theta v lambda
g = 9.81
m = 9.2;
r = 30;
eq1 = F_t*cos(delta) - F_a*cos(theta) + m*g*sin(beta_c)
eq2 = (m*v^2)/r - F_t*sin(delta) - m*g*cos(beta_c)*cos(lambda) - F_a*sin(theta)
solve([eq1, eq2], [F_t, theta])

I know that a solution exists (other CAS systems can find them), even though the result is quite complex.
But solve just hangs, no error message, no result.
Any idea?

Uwe


#2

You haven’t defined beta_c and others. Was that on purpose so that the solution is a symbolic expression in these variables?


#3

Indeed, I would like to have a symbolic solution. The following code works already:

using SymPy
@syms F_t F_a v theta lambda delta
g = 9.81
m = 9.2
r = 30.0
beta_c = 25*pi/180.0
eq1 = F_t*cos(delta) - F_a*cos(theta) + m*g*sin(beta_c)
eq2 = (m*v^2)/r - F_t*sin(delta) - m*g*cos(beta_c)*cos(lambda) - F_a*sin(theta)
solve([eq1, eq2], [F_t, theta])

It takes a few minutes to solve. So perhaps the original task would also find a solution, if I wait long enougth. Any ideas how to improve the performance?

Uwe