Solution
= Solution
Use the <substitution> $u=x^2$, so $du=2x\,dx$. The <antiderivative> is
$$
\boxed{\int4xe^{x^2}\,dx=2\int e^u\,du=2e^{x^2}+C.}
$$
Differentiation by the <chain rule> gives $4xe^{x^2}$, verifying the result.
= Solution
Use the <substitution> $u=x^2$, so $du=2x\,dx$. The <antiderivative> is
$$
\boxed{\int4xe^{x^2}\,dx=2\int e^u\,du=2e^{x^2}+C.}
$$
Differentiation by the <chain rule> gives $4xe^{x^2}$, verifying the result.