Question

Write the sum using summation notation, assuming the suggested pattern continues.
-8 - 3 + 2 + 7 + ... + 67

Answer 1

@amistre64

Answer 2

@hartnn

Answer 3

you need to define the rule, or pattern

Answer 4

This is the one with the big E in it

Answer 5

i know, but the meat of it is the rule that defines the sequence

Answer 6

\[\sum_{n=a}^{b}~f(n)\]

Answer 7

does your material want you to start with n=0? or n=1? different authors choose different starting indexes

Answer 8

yeah like that!

Answer 9

the bottom of the E is n = 0

Answer 10

you still need to define the rule for f(n)

Answer 11

idk how to do that :l

Answer 12

\[\large \sum_{n=0}^{b}~f(n)\]

Answer 13

Can i show u my the choices? its only 4

Answer 14

you have a sequence of numbers ....

-8, -3, 2, 7, ... , 67

look in your bag of "knowledge" and determine what you see happening

Answer 15

its increasing by 5 each time. eventually it gets up to 67.
first term is -8

Answer 16

then lets go with a arithmetic sequence rule:

-8 +5n , assuming we want n to start at 0

what is the value of n what this thing is equal to 67?

Answer 17

n = 15

Answer 18

so 15 on top, n = 0 on bottom

Answer 19

our rule for f(n) is -8+5n

at n=0, -8+5(0) = -8

at n=15, -8+5(15) = 67

\[\large \sum_{n=0}^{15}~-8+5n\]

works fine

Answer 20

yeahhh! thanks amistre!

Answer 21

yw