Question

The Side a square is increasing at the rate of 0.2cm/s. Find the rate of increase of the perimeter of the square?

Answer 1

Perimeter of Square = 4 x Length

Rate Of Change of 1 Side = 0.2 cm/s

Rate of Change of Perimeter = Sum of Rate of Change of all 4 sides = 4 x 0.2 cm/s
= 0.8 cm/s

Answer 2

let the side of square be X cm at any instant of time and p be it's perimeter

Now :- dx/dt = 0.2cm/s

p=4x

so

dp/dt = 4*dx/dt

dp/dt= 4*0.2=0.8cm/s