Problem
\( \int x^{3} e^{x^{2}} d x \)
Solution
Step 1 ：\( u = x^{2} \)
Step 2 ：\( du = 2x dx \)\( \Rightarrow dx = \frac{du}{2x} \)
Step 3 ：\( \int x^{3} e^{x^{2}} d x = \int x^{3} e^{u} \frac{du}{2x} \)
Step 1 ：\( u = x^{2} \)
Step 2 ：\( du = 2x dx \)\( \Rightarrow dx = \frac{du}{2x} \)
Step 3 ：\( \int x^{3} e^{x^{2}} d x = \int x^{3} e^{u} \frac{du}{2x} \)
