B$3($a$)$ Evaluate using integration by parts: ${\displaystyle \underset{6}{\overset{0}{}}}(2+5x)e^{\frac{1}{3}x}dx$

$(7$ marks$)$

$($b$)$ Integrate using substitution: ${\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}(15t^{-2}-5t)cos(6t^{-1}+t^2)dt$

$(5$ marks$)$

$($c$)$ Integrate using integration by partial fractions: ${\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{x^4+x^3+x^2+1}{x^2+x-2}dx$

$(8$ marks$)$