Elitmus
Exam
Numerical Ability
Geometry
A right circular cone is of height 1m and radius 6m. what is the maximum volume of cylinder that can be cut from this cone???
a) π 2√3
b) 16π/3
c) 9π/2
d) dnt remember
Read Solution (Total 16)
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- b) 16π/3
maxm volume of cylinder can be cut for
r = 4 m, h = 1/3 m [use concept of maxima & minima]
vol = pi*4^2*(1/3) = 16*pi/3 - 10 years agoHelpfull: Yes(30) No(17)
- radius of cylinder will be 3...and height will be reduced to 1/2...
so volume will be 9 pie/2 - 10 years agoHelpfull: Yes(17) No(7)
- http://www.mathalino.com/reviewer/differential-calculus/cylinder-maximum-volume-and-maximum-lateral-area-inscribed-cone
- 10 years agoHelpfull: Yes(12) No(2)
- answer 9pi/2
height will be half as well radius will also decreased by 50% and now taking radius as 6/2=3 and height as 1/2 calculate pi*3^2*1/2=9pi/2 - 10 years agoHelpfull: Yes(4) No(3)
- answer is 16n/3....
explanation.
we will have to use differentiation technique to get result...consider a cylinder of radius x and height 1-y...and y will be the height of rest of the cone coz total height is 1....to get the volume of cylinder in terms of y..follow simly of trngle...we will reach...x=6*y....
lets volume of cylinder be v=pie*r*r*h...this implies pie*36*y^2*(1-y)..differentiate v wrt y.. and to get max volume it will be made eyual to zero.
we will get y=2/3..and x=4...required volume will be pie*4*4*(1-2/3) i.e 16pie/3 - 10 years agoHelpfull: Yes(4) No(10)
- 1-h/1 = r/6 h = hight of cylinder , r = radius of cone.(using ~ triangle concept)
h = r-6/6
dV/dr=0, v= 1/3*pi*r^2*(r-6/6) (V of cone)
r=4 , h= 1/3.
then volume of cyl. = pi*r^2*h = Pi*16/3.
- 10 years agoHelpfull: Yes(4) No(3)
- 1-h/1 = r/6 h = hight of cylinder , r = radius of cone.(using ~ triangle concept)
h = 1-r/6
dV/dr=0, v= 1/3*pi*r^2*(1-r/6) (V of cone)
r=4 , h= 1/3.
then volume of cyl. = pi*r^2*h = Pi*16/3. - 10 years agoHelpfull: Yes(2) No(1)
- damm sure ans is 16pi/3
- 10 years agoHelpfull: Yes(2) No(1)
- Let the radius of cylinder=x;height of cylinder=h;
y is the length from vertex of the cone to the top surface of the cylinder
y/x=6/1;
Volume of cylinder=pi*x^2*h;
h=6-(6*x);
Volume=pi*x^2*(6-(6*x))
Now to get the maximum volume we have to differentiate Volume with respect to x
6*pi[2x-3x^2]=0;
x=2/3;
Therefore h=6-6*2/3;
h=2;
Volume=pi*(2/3)^2*2;
Volume=8pi/9; - 10 years agoHelpfull: Yes(1) No(3)
- how? can u explain in details?
- 10 years agoHelpfull: Yes(0) No(0)
- 64pie/3
- 10 years agoHelpfull: Yes(0) No(2)
- 4th) option is 8pi/9 and this is the answer.I am 100% sure
- 10 years agoHelpfull: Yes(0) No(2)
- c)9pie/2
take radius of cylinder x and by similarity find the height of cylinder in terms of radius and height of cone.
h1=h(r-x)/r
where h1 is height of cylinder
h height of cone
r raidus of cone
and x radius of cylinder.
Now v=pie*r^2h1,put value n diff in term of x...
use maxima n minima concept to conform the maximum volume at x=r/2.
also h1 =h/2.
put value get d result. - 10 years agoHelpfull: Yes(0) No(0)
- assume six possible cylender by deviding redis and hight in equally ratio
where height =(1/6,/6,/6,/6,/6,/6) and ratio= (1,1,1,1,1,1)
then volum of cylender are
pi*25*1/6=4.166pi
pi*16*(1/6)*2=5.34pi
pi*9*(1/6)*3=4.5pi
pi*4*(1/6)*4=2.7pi
pi*1*(1/6)*5=0.84pi
- 10 years agoHelpfull: Yes(0) No(1)
- radious........@ratio
- 10 years agoHelpfull: Yes(0) No(0)
- thanks @sujoy das
- 10 years agoHelpfull: Yes(0) No(1)
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