6. (calculator not allowed)\n\\(\\int\\frac{x^{2}}{e^{x^{3}}}dx =\\)\n(a) \\(-\\frac{1}{3}\\ln…

6. (calculator not allowed)\n\\(\\int\\frac{x^{2}}{e^{x^{3}}}dx =\\)\n(a) \\(-\\frac{1}{3}\\ln e^{x^{3}}+c\\)\n(b) \\(-\\frac{e^{x^{3}}}{3}+c\\)\n(c) \\(-\\frac{1}{3e^{x^{3}}}+c\\)\n(d) \\(\\frac{1}{3}\\ln e^{x^{3}}+c\\)\n(e) \\(\\frac{x^{3}}{3e^{x^{3}}}+c\\)
Answer
Explanation:
Step1: Use substitution
Let $u = x^{3}$, then $du=3x^{2}dx$, and $x^{2}dx=\frac{1}{3}du$.
Step2: Rewrite the integral
The integral $\int\frac{x^{2}}{e^{x^{3}}}dx$ becomes $\frac{1}{3}\int\frac{1}{e^{u}}du=\frac{1}{3}\int e^{-u}du$.
Step3: Integrate $e^{-u}$
We know that $\int e^{-u}du=-e^{-u}+C$. So, $\frac{1}{3}\int e^{-u}du =-\frac{1}{3}e^{-u}+C$.
Step4: Substitute back $u = x^{3}$
We get $-\frac{1}{3e^{x^{3}}}+C$.
Answer:
C. $-\frac{1}{3e^{x^{3}}}+C$