HELP! functions?
The velocity "v" if the airstream through an average-sized throat is related to the radius "r" of the throat (in cm) by the function:
v(r)=3.2(1-r)r^2, 0.5

Question

HELP! functions? 
The velocity "v" if the airstream through an average-sized throat is related to the radius "r" of the throat (in cm) by the function:
v(r)=3.2(1-r)r^2,     0.5<=r<=1
Determine value r for which v is a maximum?

Please help me :)
<= means less than or equal to

cwrw238 · Answer

use differentiation
v(r) = 3.2r^2 - 3.2r^3
v' =6.4r - 9.6r^2

for maxm r :
6.4r - 9.6r^2 = 0
3.2r(2 - 3r) = 0

3r = 2
r = 2/3  or 0.67 cm to 2 dec places

cwrw238 · Answer

* for maxm v:

cwrw238 · Answer

ok ? are you familiar with calculus?

anonymous · Answer

no, i'm only in algebra 2... is there any way to do this with material i would know?

anonymous · Answer

someone help please! :)