Theorem: ValidModel.r_of_a4 (ECTate/Algebra/EllipticCurve/Model.lean)

State before:
R : Type u
inst✝ : CommRing R
e : ValidModel R
r : R
⊢ (rst_iso r 0 0 e).toModel.a4 = e.a4 + 2 * r * e.a2 + 3 * r ^ 2
Tactic:
simp only [rst_iso, Model.rst_iso, one_pow, zero_mul,
sub_zero, mul_zero, one_mul, add_zero, mul_assoc, ←pow_two r]
State after:
no goals