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试题
类型:口算和估算
难度系数:0.64
所属科目:小学数学
估算
21×11≈                 49×50≈                 53×19≈                 19×21≈
69×12≈                 19×47≈                 37×89≈                 39×47≈
59×76≈                 29×73≈                 89×45≈                 62×44≈
31×56≈                 18×86≈                 19×43≈                 31×28≈
51×77≈                 13×49≈                 41×87≈                 28×85≈
61×40≈                 30×69≈                 33×29≈                 29×53≈
29×30≈                 42×19≈                 38×62≈                 59×25≈
21×38≈                 88×20≈                 32×59≈                 83×51≈
35×19≈                 62×17≈                 29×82≈                 31×68≈
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优质答疑

y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2

用户名称
2019-09-19

y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2

用户名称
2019-09-19
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