Question

下限是负无穷,上限是正无穷,x乘以e的负二分之A方X方,怎么积分啊 A是常数

Answer 1

∫xe^[(-A^2)(x^2)/2]dx=0.5∫e^[(-A^2/2)(x^2)]d(x^2)=0.5×(-2/A^2)×e^[(-A^2/2)(x^2)]=-e^[(-A^2/2)(x^2)]/A^2

代入上下限,可得极限值都是0,所以原积分=0.