Mathematics

Problem

A temperature sensor converts voltage

V

(in volts) to temperature

T

(in °C) according to the model

T=\sqrt{40V+9}

for

V>0

. When the sensor indicates

T=9^\circ\!\text{C}

, what is the instantaneous rate of change of voltage with respect to temperature,

\dfrac{dV}{dT}

, in volts per degree Celsius? a)

\dfrac{20}{9}

\dfrac{9}{20}

\dfrac{9}{40}

\dfrac{1}{4}