Posted by Anonymous on .
Could someone explain this please? Thank you.
Express the series 11+18+27+...171 using sigma notation.
a1+a2+a3+...ak
11+18+27+...171

Math 
Kate,
S = 11 + 18 + 27 + 38 + 51 + 65 + 82 + .........+Tn
S = 11 + 18 + 27 + 38 + 51 + 65 + ................ + Tn
...
0 = 11 + (7 + 9 + 11 + 13 + ....(n1).terms.................)  Tn
0 = 11 + (n  1)/2 [14 + 2(n  2)] = 11 + (n  1)(n + 5)  Tn
Tn = n^2 + 4n + 6. The given series in sigma notation is as follows.
SIGMA[k^2 + 4k + 6] the lower limit being k = 1 and the upper limit k = n