Question Number 105155 by mohammad17 last updated on 26/Jul/20

Answered by mathmax by abdo last updated on 26/Jul/20

∫_(−∞) ^(+∞)  π e^(−(α^2 /2)) dα =π ∫_(−∞) ^(+∞ )  e^(−(α^2 /2))  dα =_((α/(√2))=x)  π ∫_(−∞) ^(+∞)  e^(−x^2 ) (√2)dx  =π(√2)×(√π)=π(√(2π))