The formula for volume of cone is:
V = π
r^2 h / 3
or
π r^2
h / 3 = 36 cm^3
Simplfying in terms of r:
r^2 = 108 / π h
To find for the smallest amount of paper that can create
this cone, we call for the formula for the surface area of cone:
S = π
r sqrt (h^2 + r^2)
S = π
sqrt(108 / π h) * sqrt(h^2 + 108 / π h)
S = π sqrt(108 / π h) * sqrt[(π h^3 + 108) / π h]
Surface area = sqrt (108) * sqrt[(π h + 108
/ h^2)]
<span>Getting the 1st derivative dS / dh then
equating to 0 to get the maxima value:</span>
dS/dh = sqrt (108) ((π – 216
/ h^3) * [(π h + 108/h^2)^-1/2]
Let dS/dh = 0 so,
π – 216
/ h^3 = 0
h^3 = 216 / π
h = 4.10
cm
Calculating
for r:
r^2 = 108 / π (4.10)
r = 2.90 cm
Answers:
h = 4.10 cm
<span>r = 2.90 cm</span>
Answer:
21 students
Step-by-step explanation:
90 x .10 = 9
80 x .15 = 12
9 + 12 = 21 students
It is true because
when you separate 2y^2 +9y -18, you are supposed to get the factors
(2y-3)(y+6), when you multiply this it gives you the first equation, we know
this because when we multiply the first term it gives us exactly 2y^2 and if we
multiply the last ones it gives you -18, now here is the tricky part, when we
multiply the middle part we get 12y and -3y, when we add these up we get 9y,
now is that the same middle as in the equation? Yes… then our factors are correct
making this true
Hope this helps
Answer :
1 one, it's one hoped this help !
