Question

19. Evaluate the sum
7
S (4 k^2+k)
k=5


Possibilities:
(a) 458
(b) 459
(c) 460
(d) 461
(e) 462

Answer 1

the S is the Sigma sign

Answer 2

why is the answer A?

Answer 3

\[\sum_{k=5}^{k=7} (4k^2+k)\]
As there are only three sums, we can manually evaluate
\[((4 \times 5^2+5)+( 4\times 6^2+6)+(4 \times 7^2+7))\]
We have
\[ ( (100+5)+(144+6)+(196+7)\]
\[(105)+(150)+(203)=458\]

Answer 4

o so i dont have to subtract 5 from 7 and add 1 so k=1?

Answer 5

no you have to sum from 5 to 7