Question 637371
  <pre><font face = "Tohoma" size = 3 color = "indigo"><b> 
Hi,
{-25, ...26}  Arithemetic Sequence, d = 1  and {{{a[1] = -25}}}
{{{a[n] = -25 + (n-1) = 26}}},   n = 52
{{{S[n]=(n(a[1]+a[n]))/2}}}
{{{S[52]= (52(-25 + 26))/2 = 26 }}}
0r
{{{S[n]=(n/2)(2*a[1]+ (n-1)d)}}}
{{{S[52]=(26)(-50+ (51)*1)= 26}}}