Selecting Techniques for Antidifferentiation Practice Test

A signal filter uses $\int \frac{1}{\sqrt{4-x^2}},dx$; which technique is most appropriate?

A biologist models nutrient uptake by $U(t)=\int_0^t \frac{6x}{x^2+4},dx$; which technique best finds $U'(t)$’s antiderivative form?