syms T R L C E D
T = R+L+C-E
eq1= D == 180-1/cos((T^2+R
^2) /(2*R*T))
solve(eq1,E)
Solving for E equals 1 of 4 equations
E = C + L + R - pi*R + R*acos(1/(D - 180)) - (L^2 - R^2 + R^2*pi^2 + R^2*acos(1/(D - 180))^2 - 2*pi*R^2*acos(1/(D - 180)))^(1/2)
E = C + L + R - pi*R - R*acos(1/(D - 180)) - (L^2 - R^2 + R^2*pi^2 + R^2*acos(1/(D - 180))^2 + 2*pi*R^2*acos(1/(D - 180)))^(1/2)
E = C + L + R - pi*R + R*acos(1/(D - 180)) + (L^2 - R^2 + R^2*pi^2 + R^2*acos(1/(D - 180))^2 - 2*pi*R^2*acos(1/(D - 180)))^(1/2)
E = C + L + R - pi*R - R*acos(1/(D - 180)) + (L^2 - R^2 + R^2*pi^2 + R^2*acos(1/(D - 180))^2 + 2*pi*R^2*acos(1/(D - 180)))^(1/2)