Question

a1=-2, d=-3
What are the first four terms of the sequence?

-3, -5, -7, -9

-2, -5, -8, -11

-2, 1, 4, 7

1, -2, -5, -8

Answer 1

Arithmetic sequence?

Answer 2

add -3 to get the terms

Answer 3

15

5

14

10

Answer 4

An arithmetic sequence is a pretty nice little sequence to work with. Every term has the same difference from the one before it. For example, look at this sequence
2, 5, 8, 11, 14
What's the pattern?

Answer 5

3?

Answer 6

like, +3?

Answer 7

Yup. To get the next term, just add 3.

Answer 8

So then it would be -2, -5, -8, -11 for number 1?

Answer 9

When we're defining an arithmetic sequence, we'll say something like,
"a1 = ? and d="
The d part is what you add each time.
The a1 part is what the very first term is, or what you start with.

So that sequence would be
d=3 and a1=2

Answer 10

Right =D

Answer 11

Yay! Ok

Answer 12

How do you do #2 then?

Answer 13

Haha okay, that kind of problem is totally different. Let me try to explain summation notation to you.

Answer 14

Think of summation notation as instructions for adding up a bunch of numbers.

Answer 15

I'll do this as an example.