no goals
R✝ : Type ?u.363887
inst✝² : Semiring R✝
f : R✝[X]
R : Type u_1
inst✝¹ : Ring R
inst✝ : NoZeroDivisors R
p q : R[X]
⊢ trailingCoeff (p * q) = trailingCoeff p * trailingCoeff q
rw [← reverse_leadingCoeff, reverse_mul_of_domain, leadingCoeff_mul, reverse_leadingCoeff,
  reverse_leadingCoeff]