The function h= is used to model fireworks being launched (or projected) into the air. The function models the height h after x seconds.

a) How long will it take the fireworks to reach their greatest height?
b) How high will the fireworks be their greatest height?

Question

The function h=   is used to model fireworks being launched (or projected) into the air.  The function models the height h after x seconds.

	a)  How long will it take the fireworks to reach their greatest height?       
	b)  How high will the fireworks be their greatest height?

anonymous · Answer

$$h=-16x ^{2}+160x+4$$

xapproachesinfinity · Answer

to find the max height you need to take derivative

trojanpoem · Answer

Find maxima using derivative as xapproaches said then you will get the time put it in the main function and you will get the height.

xapproachesinfinity · Answer

$\frac{dh}{dx}=-32x+160$
set this equal 0 to find the time it takes to reach maximum

anonymous · Answer

hello mam, i would like to know whether u are used to taking derivatives..?

xapproachesinfinity · Answer

you can actually discard calculus and do it with basic tools

xapproachesinfinity · Answer

that's just a parabola!
and you learned that the prabolas has max at $\left (\frac{-b}{2a}, h(\frac{-b}{2a})\right )$

xapproachesinfinity · Answer

when a<0 that is

xapproachesinfinity · Answer

a being the leading coefficient!