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I hava function $F(X,Y)$.

$X(t)$ and $Y(t)$ : both are functions of a third variable $t$.

In addition $X(Y(t), t)$: $X$ is a function of $Y$, which is a function of $t$, and $t$.

The third point is strange but this is a theoretical model, there are no actual functions to substitute in (in particular I cannot substitute $Y(t)$ simply with a polynomial of $t$ or the functional form).

I need to calculate $dF/dt$ : the partial derivative of the function with respect to $t$.

My solution:

$$ \frac{dF}{dt} = \frac{dF}{dX} \left( \frac{dX}{dY} \times \frac{dY}{dt} + \frac{dX}{dt} \right) + \frac{dF}{dY} \times \frac{dY}{dt} $$

($\times$ are product signs)

Do you think it is correct?

Thank you for your time.

user251257
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