∫_(-∞)^(+∞)▒1/(x^2+2x+2) dx=∫_(-∞)^(+∞)▒1/((x+1)^2+1) dx□((x+1=t) ⇒ ) ∫_(-∞)^(+∞)▒1/(t^2+1) dt=∫_(-∞)^(+∞)▒d(arctant) =π
