Question

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Answer 1

\[\sum2a_n+n=2\sum a_n+\sum n\]

Answer 2

one of these numbers on the right you are told,
we have
\[2\times 10+\sum_{n+1}^{100}n\] and the second term should be easy to compute

Answer 3

Am I just supposed to end up with a numerical answer?

Answer 4

yes

Answer 5

\(2\times 10=20\) is the first number
do you know how to compute
\[\sum_{n=1}^{100}n\]?

Answer 6

It would be 5050 right? I looked it up but I'm not sure how to actually compute that without looking it up

Answer 7

\[\sum_{n=1}^kn=\frac{k(k+1)}{2}\] and so
\[\sum_{n=1}^{100}n=\frac{(100)(101)}{2}=50\times 101\]

Answer 8

So it would just be 5070 then?

Answer 9

yes

Answer 10

Okay thanks :)

Answer 11

yw