Question

Help! I'll fan and medal
Find the sum of the summation of 3 i plus2, from i equals 5 to 13

Answer 1

You mean
\[\sum_{5}^{13}3i+2\]

Answer 2

yes except where the 5 is, it says i=5

Answer 3

Hint: \(\sum_{i=5}^{13}3i+2=3\sum_{i=5}^{13}i+\sum_{i=5}^{13}2=3\sum_{i=5}^{13}i+2\sum_{i=5}^{13}1\)

Answer 4

These are really confusing me for and I'm not sure how to do them

Answer 5

mods? i need help it won't let me post a question without paying

Answer 6

Do you know how to find \(\sum_{i=5}^{13}i\)


?

Answer 7

No

Answer 8

Yes, It's 9i

Answer 9

\(\sum_{i=1}^{n}i=\dfrac{n(n+1)}{2}\)

So we have \(\sum_{i=5}^{13}i=\sum_{i=1}^{13}i-\sum_{i=5}^{5}=\dfrac{13*14}{2}-\dfrac{5*6}{2}\)

Answer 10

that should say

\(\sum_{i=5}^{13}i=\sum_{i=1}^{13}i-\sum_{i=4}^{5}=\dfrac{13*14}{2}-\dfrac{4*5}{2}\)

Answer 11

That makes more sense

Answer 12

so

\(\sum_{i=5}^{13}3i+2=3\sum_{i=5}^{13}i+\sum_{i=5}^{13}2=3\sum_{i=5}^{13}i+2\sum_{i=5}^{13}1\\=3(\dfrac{13*14}{2}-\dfrac{4*5}{2})-2(9)\)

Answer 13

Alright, I'm gonna see if I can solve it

Answer 14

got to go, good luck. Ill check back later.