Could anyone please help me with these integration problems? You don't have to give me the answers, but if you could point me in the direction to get started, I'd really appreciate it.

Thanks in advance!

1. $\displaystyle \int\frac{1}{\sqrt{25-7t^2}}~dt$

2. $\displaystyle \int\frac{x^3}{x^2-2x+3}~dx$

3. $\displaystyle \int e^{3x}cos{4x}~dx$