Question

What is the partial sum of ?

a 2,272
b –2,208
c –2,272
d 2,208

Answer 1

\[\sum_{i=10}^{25} -2-8i\]

Answer 2

it is negative for sure, since all the terms are

Answer 3

of course it is C
answer is always C

Answer 4

Can I have the real answer? or if this is the real answer can you show me how you got it? Thanks

Answer 5

@Chlorophyll

Answer 6

C is the real answer

Answer 7

Okay, how do you get it?

Answer 8

there is a snap way to do this, but i do not know it. i compute
\[\sum_{i=1}^{25}-2-8i -\sum_{i=1}^9-2-8i\]

Answer 9

Thank you

Answer 10

first one is easy enough, it is
\[\sum_{i=1}^{25}-2-8\sum_{i=1}^{25}i\]
\[=-50-8\times \frac{25\times 26}{2}=-50-4\times25 \times 26\]
\[=-50-2600=-2650\]
second part is similar

Answer 11

That answer is not an option, but thank you anyway

Answer 12

oh that was just the first part,

Answer 13

Oh, alright

Answer 14

you still have to compute
\[\sum_{i=1}^9-2-8i\] and subtract it from the answer i wrote above.
C is the final answer

Answer 15

Thanks!