no goals
x y : ℝ
hx : x ∈ Icc (-(π / 2)) (π / 2)
hy : y ∈ Icc (-1) 1
⊢ x ≤ arcsin y ↔ sin x ≤ y
rw [← neg_le_neg_iff, ← arcsin_neg,
  arcsin_le_iff_le_sin ⟨neg_le_neg hy.2, neg_le.2 hy.1⟩ ⟨neg_le_neg hx.2, neg_le.2 hx.1⟩, sin_neg,
  neg_le_neg_iff]