Question

Evaluate $\underset{1}{\overset{3}{\int }}3x^2+2x+1dx$

Answer 1

${\int }_a^{b}n\times x^{n-1}dx=[x^n{]}_a^b$

${\int }_1^3(3x^2+2x+1)dx=[x^3+x^2+x{]}_1^3=[3^3-1]+[3^2-1]+[3-1]=36$