import sympy as sm
sm.init_printing()
mb, mc, Ib, Ic, r, l, d = sm.symbols('m_b, m_c, I_b, I_c, r, l, d')
mb
Ib
r+Ib**2
sm.sin(r) + sm.sqrt(mb)
t = sm.symbols('t')
theta = sm.Function('theta')(t)
theta
omega = sm.Function('omega')(t)
omega
sm.diff(theta, t)
sm.diff(theta**2+sm.sin(theta**2/2), t)
h = l - sm.sqrt(l**2 - d**2)
h