Integral

Beräkna integralen:

${\int }_1^2(3x^2+x)dx$

Min lösning:

${\int }_1^2(3x^2+x)dx\left[\begin{array}{c}{x}^2\\ 2\end{array}+x^3\right]\underset{1}{\overset{2}{}} =\frac{ 2^2}{2} + 2^3 - (\frac{1^2}{2} + 1^3) = 8.5$

Rätt?