Mathematics

Mathematics

Problem

The volume VV (in cm3^{3}) of a gas is related to its temperature TT (in K) by V=5T2+3TV = 5T^{2} + 3T. The temperature varies with time tt (in seconds) according to T=2t+273T = 2t + 273. Calculate dVdt\dfrac{dV}{dt} at t=10 st = 10\,\text{s}.
Intuitive explanation

This problem chains together two relationships: volume depends on temperature, and temperature depends on time. You need the chain rule to find how volume changes with time directly. Rather than substituting TT into VV first, recognize that dVdt=dVdT⋅dTdt\frac{dV}{dt} = \frac{dV}{dT} \cdot \frac{dT}{dt}—find each piece separately, then multiply them together at the specific moment t=10 st = 10\,\text{s}.

Intuitive explanation

This problem chains together two relationships: volume depends on temperature, and temperature depends on time. You need the chain rule to find how volume changes with time directly. Rather than substituting TT into VV first, recognize that dVdt=dVdT⋅dTdt\frac{dV}{dt} = \frac{dV}{dT} \cdot \frac{dT}{dt}—find each piece separately, then multiply them together at the specific moment t=10 st = 10\,\text{s}.

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