a) \(I_1=\int\dfrac{dx}{x^2+2x+3}\)
\(=\int\dfrac{dx}{\left(x+1\right)^2+2}=\int\dfrac{d\left(x+1\right)}{\left(x+1\right)^2+\left(\sqrt{2}\right)^2}\)
\(=\dfrac{1}{\sqrt{2}}arctan\left(\dfrac{x+1}{\sqrt{2}}\right)+C\)
b) \(I_2=\int\dfrac{dx}{4x^2+4x+2}\)
\(=\int\dfrac{dx}{\left(2x+1\right)^2+1}=\dfrac{1}{2}\int\dfrac{d\left(2x+1\right)}{\left(2x+1\right)^2+1^2}\)
\(=\dfrac{1}{2}arctan\left(2x+1\right)+C\)