It is about finding expression for volume?

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1 Answer
May 9, 2018

Let half of the base of isoscles triangle of height h cm after t sec of start of filling the tank be x cm.

So hx=tan30x=3h.

So the area of triangular surface of water of height will be

A=xh=3h2 cm2

(1) Volume of water at t th sec will be V=A40=403h2cm3

(2) The rate of pouring water in the tank is 200cm3/s.

So the amount of water poured in t sec will be 200tcm3

Hence

403h2cm3=200t

h2=53t

Differentiating w .r to t we get

2hdhdt=53

dhdt=523h

So rate of increasing height when h=5cm will be
[dhdt]h=5=5235=36cms1