Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 12-science Answered

An open tank with a square base and vertical sides is to be constructed from a metal sheet so as to hold a given quantity of water. Show that the cost of the material will be least when the depth of the tank is half of its width.
Asked by Manoj | 04 Sep, 2013, 04:41: AM
answered-by-expert Expert Answer
 
begin mathsize 16px style Let space length comma space width space and space depth space of space the space tank space be space straight l comma straight l space and space straight h space respectively.
Volume space of space the space tank space equals space straight l squared straight h
Total space surface space area space equals space straight l squared plus 4 lh
straight v equals straight l squared straight h
straight h equals straight v over straight l squared....... left parenthesis straight i right parenthesis
Surface space area space equals space space straight l squared plus 4 lh
straight S equals space straight l squared plus 4 straight l cross times straight v over straight l squared
straight S equals space straight l squared plus 4 cross times straight v over straight l
rightwards double arrow dS over dl equals 2 straight l minus fraction numerator 4 straight v over denominator straight l squared end fraction
dS over dl equals 0
2 straight l minus fraction numerator 4 straight v over denominator straight l squared end fraction equals 0
rightwards double arrow straight l cubed equals 2 straight v
rightwards double arrow straight l equals 2 straight h.......... from space left parenthesis straight i right parenthesis
dS squared over dl squared equals 2 plus fraction numerator 8 straight v over denominator straight l cubed end fraction greater than 0
Hence comma space cost space material space will space be space least space when space the space depth space of space the space tank space is space half space of space its space width.
end style
Answered by | 11 Dec, 2017, 02:05: PM

Concept Videos

CBSE 12-science - Maths
Asked by srisrinivasa.mcrl | 04 Feb, 2024, 10:39: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Maths
Asked by tv2000in | 28 May, 2019, 12:02: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Maths
Asked by Kchawla94 | 02 Apr, 2019, 06:45: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Maths
Asked by Topperlearning User | 21 Aug, 2014, 01:22: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Maths
Asked by Topperlearning User | 19 Aug, 2014, 09:25: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
Get Latest Study Material for Academic year 24-25 Click here
×