thanks
3 Answers
sagnik sarkar
·2010-07-24 01:49:39
cot-12n2=tan-11/2n2
=tan-1(2/4n2)=tan-1[(2n+1)-(2n-1)]/1+4n2-1
=tan-12n+1-tan-12n-1
Find sum upto n terms and aplly limit!
dmaga
·2010-07-24 01:56:57
i tried like
tan-1(1/2+2nn-2)=tan-1[(n+1)-(n-1)]/1+(n+1)(n-1)
and they didnt cancel