Concept:Use logarithmic differentiation for functions of the form f(x)g(x).Explanation:Given y=(sinx)tanx.Taking natural logarithm on both sides:logy=tanx⋅log(sinx)Differentiate both sides with respect to x:y1dxdy=sec2x⋅log(sinx)+tanx⋅sinx1⋅cosxSince tanx⋅cotx=1, we get:y1dxdy=sec2xlog(sinx)+1Multiply by y=(sinx)tanx:dxdy=(sinx)tanx(1+sec2xlog(sinx))Answer:Option A: (sinx)tanx(1+sec2xlog(sinx))