부정적분

$f \left( x \right)$$\displaystyle = \int _{} ^{} {} \left( 9 x ^{2} + 4 x \right) dx$ $= 3 x ^{3} + 2 x ^{2} + C$ (단, $C$는 적분상수) $f \left( 1 \right) = 6$이므로 $f \left( 1 \right) = 3 + 2 + C = 6$, $C = 1$ 따라서 $f \left( x \right) = 3 x ^{3} + 2 x ^{2} + 1$이므로 $f \left( 2 \right) = 3 \times 2 ^{3} + 2 \times 2 ^{2} + 1 = 33$