Question
Let the equation of a curve passing through the point $$\left( {0,\,1} \right)$$ be given by $$y = \int {{x^2}.{e^{{x^3}}}} dx.$$ If the equation of the curve is written in the form $$x = f\left( y \right)$$ then $$f\left( y \right)$$ is :
A.
$$\sqrt {{{\log }_e}\left( {3y - 2} \right)} $$
B.
$$\root 3 \of {{{\log }_e}\left( {3y - 2} \right)} $$
C.
$$\root 3 \of {{{\log }_e}\left( {2 - 3y} \right)} $$
D.
none of these
Answer :
$$\root 3 \of {{{\log }_e}\left( {3y - 2} \right)} $$
Solution :
$$\eqalign{
& y = \int {\frac{1}{3}{e^{{x^3}}}d\left( {{x^3}} \right)} = \frac{1}{3}{e^{{x^3}}} + c \cr
& {\text{It passes through }}(0,{\text{ }}1) \cr
& \therefore 1 = \frac{1}{3}{e^0} + c \cr
& \therefore c = \frac{2}{3}.{\text{ Hence, }}y = \frac{1}{3}\left( {{e^{{x^3}}} + 2} \right) \cr
& \therefore {e^{{x^3}}} = 3y - 2\,\,\,\,\,\,\,\,\,\,\therefore x = \root 3 \of {{{\log }_e}\left( {3y - 2} \right)} \cr} $$