1.判断题:石棉网在加热过程中能使蒸发皿受热均匀。(_____)
2.正确使用酒精灯的方法是( )。
A.打开灯帽一点燃酒精灯一用外焰加热一用嘴吹灭 |
B.打开灯帽一点燃酒精灯一用焰心加热一用灯帽盖灭 |
C.打开灯帽一点燃洒精灯一用外焰加热一用灯帽盖灭 |
A.全都不见了 | B.液体越来越多 | C.有颗粒粘在蒸发皿中 |
同类型试题
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
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