Question

\text { If } f(x, y)=x^{2}+2 x y, x=s \ln (t) \text { and } y=t^{3}+s^{3}, \text { then } \frac{\partial f}{\partial \varepsilon} \text { when } t=1, s=1 \text

{ is } ) In(2) 1 None of (A) - (D)

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