In [5]:
import sympy
e1, e2, d1, d2, y1, y2, d3 = sympy.symbols("e1 e2 d1 d2 y1 y2 d3")
c11, c22, c33, c44, c55, c66 = sympy.symbols("c11 c22 c33 c44 c55 c66")
c12, c13, c23 = sympy.symbols("c12 c13 c23")
e2 = (c11 - c33)/(2*c33)
d2 = ((c13 + c55)**2 - (c33 - c55)**2) / (2*c33*(c33 - c55))
y2 = (c66 - c44) / (2*c44)
e1 = (c22 - c33)/(2*c33)
d1 = ((c23 + c44)**2 - (c33 - c44)**2) / (2*c33*(c33 - c44))
y2 = (c66 - c55) / (2*c55)
S = sympy.solve([e2, d2, y2, e1, d1, y1], [c12])
print(S)
print('Done Solve')