omar
31-07-2007, 05:47 PM
أحسب نهاية المجموع S_n بحيث :
S_n = Arctan(\frac{1}{3}) + Arctan(\frac{1}{7}) +... + Arctan(\frac{1}{n^2+n+1})
Arctan(x)=\tan^{-1}(x)
S_n = Arctan(\frac{1}{3}) + Arctan(\frac{1}{7}) +... + Arctan(\frac{1}{n^2+n+1})
Arctan(x)=\tan^{-1}(x)