Find dy/dx if
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Many thanks!
Hi-
Just differentiate $\displaystyle 2y^3t+t^3y=1$ with respect to $\displaystyle x$, using the product rule to get:
$\displaystyle 2y^3\frac{dt}{dx}+3y^2\frac{dy}{dx}t +t^3\frac{dy}{dx}+3t^2\frac{dt}{dx}y=0$
Now collect together the terms in $\displaystyle \frac{dt}{dx}$ and $\displaystyle \frac{dy}{dx}$, substitute $\displaystyle \frac{dt}{dx}=\frac{1}{\cos t}$ and the job's done.
Grandad