作业帮Red aerial minifalres are used by some boaters in an emergen
来源：学生作业帮 编辑：作业帮 分类：英语作业 时间：2024/05/15 13:19:36
Red aerial minifalres are used by some boaters in an emergency.The flight of one brand of flare,when fired at an angle of 70 degrees to the horizontal,is modelled by the function:
h= -9(t-3)^2+ 83
where h is the height (m) and t is the time (sec),since the flare was fired.
a) For how many seconds does the flare burn before it hits the water?
请写出演算过程.
h= -9(t-3)^2+ 83
where h is the height (m) and t is the time (sec),since the flare was fired.
a) For how many seconds does the flare burn before it hits the water?
请写出演算过程.
数学?
It's best ＿and bring these items with you ,but in an emergen
many kinds of drugs are used by athletes competing in
In some English classes,pictures are used( )the students lea
some are red完整形式
some are red 完整形式
In some cities school buses are used only when children are
there is an ancient invention still used in some parts of th
小题1:In the past, some cultures used tattoos as an a_________
The flowers are planted_____light red. A.on B.in C.with D.by
There are some apples in the red bag.(改为单数句)
all girls wear beautiful clothes.some are dressed in red;___
the girl has some balloons in her hand.one is red,are yellow