![](http://static.xuejinqu.com/qimg/92f/92fcdb44946c35e228786bb471462a68.png)
A.生石灰与水反应,会放出大量的热 |
B.设计出气孔的目的是为了避免使用时盒内气压过高 |
C.遇水能放出热量的物质都能作为发热包的内容物 |
D.使用过的发热包即使干燥后也不能重复使用 |
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同类型试题
![](http://static.xuejinqu.com/images/medal.png)
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
![](http://static.xuejinqu.com/images/avatar.png)
![](http://static.xuejinqu.com/images/avatar.png)
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
![](http://static.xuejinqu.com/images/avatar.png)
![](http://static.xuejinqu.com/images/avatar.png)