Today we're learning Arithmetic Sequence.
Formula: An = A1 + (n - 1) d
n = The term
d = Common difference
For example, 1,3,5,7 what is the common difference (d)?
It's 2, how?
1+2 = 3
3+2 = 5
5+2 = 7
Now what is the 29th term? Do you need to do still need to plus (+) until you get the right answer? No
A29 = 1 + (29 - 1) 7
= 1 + (28) 7 - (multiply (x) the 28 and 7)
= 1 + 203
A29 = 204
Yes, the (n - 1) is always minus (-) 1
What if it is negative? -12, -8, -4, 0
Common difference is 4, Find the 7th term
A7 = -12 + (7 - 1) 4
= -12 + (6) 4 -( multiply the 6 and 4)
= -12 + 24
A7 = 12
If it has a negative number and positive number its always negative (-) in the final.
