no goals
R : Type u
S : Type v
ι : Type w
a b : R
m n : ℕ
inst✝¹ : Semiring R
inst✝ : NoZeroDivisors R
p q : R[X]
hq : natDegree q ≠ 0
⊢ leadingCoeff (comp p q) = leadingCoeff p * leadingCoeff q ^ natDegree p
rw [← coeff_comp_degree_mul_degree hq, ← natDegree_comp, coeff_natDegree]