limx趋向于无穷n2(arctan(a/n)-arctan[a/(n+1)]求极限

问题描述:

limx趋向于无穷n2(arctan(a/n)-arctan[a/(n+1)]求极限

lim+00> n²(arctan(a/n)-arctan[a/(n+1)])
=lim+00> n²(a/n-a/(n+1)) (因为arctanx~x )
=lim+00> n²(a/(n²+1))
=lim+00> a/(1+1/n²)
=a/1=a