Question Number 37795 by Rio Mike last updated on 17/Jun/18
$${The}\:{side}\:{of}\:{a}\:{square}\:{is}\:{increasing} \\ $$$${at}\:{a}\:{rate}\:{of}\:\mathrm{0}.\mathrm{1}{cms}^{−\mathrm{1}} .\:{Find}\:{the} \\ $$$${rate}\:{of}\:{increase}\:{of}\:{the}\:{perimeter} \\ $$$${of}\:{the}\:{square}\:{when}\:{the}\:{length}\:{of} \\ $$$${side}\:{is}\:\mathrm{4}{cm}. \\ $$
Answered by tanmay.chaudhury50@gmail.com last updated on 18/Jun/18
$${p}=\mathrm{4}{a} \\ $$$$\frac{{dp}}{{dt}}=\mathrm{4}\frac{{da}\:\:}{{dt}}\:\:\:\:{p}={perimeter}\:\:\:\:\:{a}={side}\:{of}\:{square} \\ $$$$\frac{{dp}}{{dt}}=\mathrm{4}×\mathrm{0}.\mathrm{1}=\mathrm{0}.\mathrm{4}{cm}/{sec} \\ $$