AP EAMCET20227 Jul 2022Evening ShiftMathematicsApplication of DerivativesActual
If an open cylinder of given surface area has maximum volume, then its radius is
Options
- AHeight of the cylinder
- BHeight of the cylinder/2
- C2 times height of the cylinder
- D3 times height of the cylinder
Correct answer
A. Height of the cylinder
Step-by-step solution
Cylinder is open, radius of base =R , height =H Surface area A=2 R H+ R^2 aligned & H= A- R^2 2 R & V= R^2 H= R^2 ( A- R^2 2 R )= R 2 (A- R^2 ) & d v d R = A 2 - 3 R^2 2 =0 A=3 R^2 & d^2 V d R^2 =-3 R < 0 & at A=3 R^2, maximum volume & A=3 R^2=2 R H+ R^2 & R=H aligned