@@ -1281,29 +1281,29 @@ match (le_total x (π / 2) : x ≤ π / 2 ∨ π / 2 ≤ x), le_total y (π / 2)
1281
1281
apply cos_lt_cos_of_nonneg_of_le_pi_div_two; linarith)
1282
1282
end
1283
1283
1284
- lemma strict_mono_decr_on_cos : strict_mono_decr_on cos (Icc 0 π) :=
1284
+ lemma strict_anti_on_cos : strict_anti_on cos (Icc 0 π) :=
1285
1285
λ x hx y hy hxy, cos_lt_cos_of_nonneg_of_le_pi hx.1 hy.2 hxy
1286
1286
1287
1287
lemma cos_le_cos_of_nonneg_of_le_pi {x y : ℝ} (hx₁ : 0 ≤ x) (hy₂ : y ≤ π) (hxy : x ≤ y) :
1288
1288
cos y ≤ cos x :=
1289
- (strict_mono_decr_on_cos .le_iff_le ⟨hx₁.trans hxy, hy₂⟩ ⟨hx₁, hxy.trans hy₂⟩).2 hxy
1289
+ (strict_anti_on_cos .le_iff_le ⟨hx₁.trans hxy, hy₂⟩ ⟨hx₁, hxy.trans hy₂⟩).2 hxy
1290
1290
1291
1291
lemma sin_lt_sin_of_lt_of_le_pi_div_two {x y : ℝ} (hx₁ : -(π / 2 ) ≤ x)
1292
1292
(hy₂ : y ≤ π / 2 ) (hxy : x < y) : sin x < sin y :=
1293
1293
by rw [← cos_sub_pi_div_two, ← cos_sub_pi_div_two, ← cos_neg (x - _), ← cos_neg (y - _)];
1294
1294
apply cos_lt_cos_of_nonneg_of_le_pi; linarith
1295
1295
1296
- lemma strict_mono_incr_on_sin : strict_mono_incr_on sin (Icc (-(π / 2 )) (π / 2 )) :=
1296
+ lemma strict_mono_on_sin : strict_mono_on sin (Icc (-(π / 2 )) (π / 2 )) :=
1297
1297
λ x hx y hy hxy, sin_lt_sin_of_lt_of_le_pi_div_two hx.1 hy.2 hxy
1298
1298
1299
1299
lemma sin_le_sin_of_le_of_le_pi_div_two {x y : ℝ} (hx₁ : -(π / 2 ) ≤ x)
1300
1300
(hy₂ : y ≤ π / 2 ) (hxy : x ≤ y) : sin x ≤ sin y :=
1301
- (strict_mono_incr_on_sin .le_iff_le ⟨hx₁, hxy.trans hy₂⟩ ⟨hx₁.trans hxy, hy₂⟩).2 hxy
1301
+ (strict_mono_on_sin .le_iff_le ⟨hx₁, hxy.trans hy₂⟩ ⟨hx₁.trans hxy, hy₂⟩).2 hxy
1302
1302
1303
1303
lemma inj_on_sin : inj_on sin (Icc (-(π / 2 )) (π / 2 )) :=
1304
- strict_mono_incr_on_sin .inj_on
1304
+ strict_mono_on_sin .inj_on
1305
1305
1306
- lemma inj_on_cos : inj_on cos (Icc 0 π) := strict_mono_decr_on_cos .inj_on
1306
+ lemma inj_on_cos : inj_on cos (Icc 0 π) := strict_anti_on_cos .inj_on
1307
1307
1308
1308
lemma surj_on_sin : surj_on sin (Icc (-(π / 2 )) (π / 2 )) (Icc (-1 ) 1 ) :=
1309
1309
by simpa only [sin_neg, sin_pi_div_two]
@@ -1661,7 +1661,7 @@ end angle
1661
1661
1662
1662
/-- `real.sin` as an `order_iso` between `[-(π / 2), π / 2]` and `[-1, 1]`. -/
1663
1663
def sin_order_iso : Icc (-(π / 2 )) (π / 2 ) ≃o Icc (-1 :ℝ) 1 :=
1664
- (strict_mono_incr_on_sin .order_iso _ _).trans $ order_iso.set_congr _ _ bij_on_sin.image_eq
1664
+ (strict_mono_on_sin .order_iso _ _).trans $ order_iso.set_congr _ _ bij_on_sin.image_eq
1665
1665
1666
1666
@[simp] lemma coe_sin_order_iso_apply (x : Icc (-(π / 2 )) (π / 2 )) :
1667
1667
(sin_order_iso x : ℝ) = sin x := rfl
@@ -1723,11 +1723,11 @@ match le_total x 0, le_total y 0 with
1723
1723
| or.inr hx0, or.inr hy0 := tan_lt_tan_of_nonneg_of_lt_pi_div_two hx0 hy₂ hxy
1724
1724
end
1725
1725
1726
- lemma strict_mono_incr_on_tan : strict_mono_incr_on tan (Ioo (-(π / 2 )) (π / 2 )) :=
1726
+ lemma strict_mono_on_tan : strict_mono_on tan (Ioo (-(π / 2 )) (π / 2 )) :=
1727
1727
λ x hx y hy, tan_lt_tan_of_lt_of_lt_pi_div_two hx.1 hy.2
1728
1728
1729
1729
lemma inj_on_tan : inj_on tan (Ioo (-(π / 2 )) (π / 2 )) :=
1730
- strict_mono_incr_on_tan .inj_on
1730
+ strict_mono_on_tan .inj_on
1731
1731
1732
1732
lemma tan_inj_of_lt_of_lt_pi_div_two {x y : ℝ} (hx₁ : -(π / 2 ) < x) (hx₂ : x < π / 2 )
1733
1733
(hy₁ : -(π / 2 ) < y) (hy₂ : y < π / 2 ) (hxy : tan x = tan y) : x = y :=
0 commit comments