[tex]\displaystyle \sf \int 4x^3\cdot sin(x^4+2) \ dx \\\\ \text{Fa{\c c}amos } : \\\\ x^4+2 = u \to 4x^3 dx = du \\\\ Da{\'i}}: \\\\ \int sin(u)\ du = -cos(u) + C \\\\ portanto : \\\\ \boxed{\sf \int 4x^3\cdot sin(x^4+2) \ dx = -cos(x^4+2) + C \ } \checkmark[/tex]
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