1. $\int t^2 \sin(8t) dt$
2. $\int \tan^2(x) \sec^4(x) dx$
3. $\int_{0}^{3} \frac{x}{\sqrt{36-x^2}} dx$
4. $\int \frac{\sqrt{1+x^2}}{x} dx$
5. $\int \frac{dx}{(x-1)(x+2)}$