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Using chain rule find $\large\frac{dw}{dt}$ for each of the following : $w=e^{xy}$ Where $x=t^{2},y=t^{3}$

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1 Answer

  • Chain rule: If $u= f(x,y)$ is differentiable and $x,y $ are functions of t then $\large\frac{du}{dt}=\frac{\partial u}{\partial x}\frac{dx}{dt}+\frac{\partial u}{\partial y} \frac{dy}{dt}$
  • The chain rule for $u(x,y,z)$ where $x,y,z$ are functions of t is similarly stated.
$w=e^{xy}$ where $x=t^2,y=t^3$
Step 1:
$\large\frac{dx}{dt}$$=2t,\large\frac{dy}{dt}$$=3t^2,\large\frac{\partial w}{\partial x}$$=ye^{xy},\large\frac{\partial w}{ \partial y}$$=xe^{xy}$
Step 2:
$\large\frac{dw}{dt}=\frac{\partial w}{\partial x}\frac{dx}{dt}+\frac{\partial w}{\partial y} \frac{dy}{dt}$
$\qquad= 5t^4e^{t^5} \qquad(x=t^2,y=t^3)$


answered Aug 13, 2013 by meena.p
edited Aug 13, 2013 by meena.p

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