Q$\mathrm{.}3($a$)$ Evaluate the following integrals for triangular elements

a$)o{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}{l}_1^2{l}_2{l}_3^{2}dA$

b$)o{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}{l}_1^2{l}_2^2{l}_3^{3}dA$