Arithmetic Sequences Review

Arithmetic Sequences Review

Poll

Do you feel ready for the quiz?

• Yes! I'm going to ace it!

• Mostly ready

• I'll be ready after the review

• Will never be ready

Arithmetic Sequences

• Recursive Formula: a₁=value; a_n=a_n-1+d

• Explicit Formula: a_n=a₁+d(n-1)

• Explicit Formula written like y=mx+b: a_n=a₀+dn

​Common Difference

• ​A fixed amount that you add or subtract to get from term to term

Multiple Choice

What are the next three terms in the arithmetic sequence 4, 1.5, -1, -3.5, ...

• -6, -8.5, -11

• -4, -5.5, -7

• 6, 8.5, 11

• a sequence cannot have negative numbers

​d = 1.5 - 4 = -2.5

​-3.5 - 2.5 = -6

​-6 -2.5 = -8.5

​-8.5 - 2.5 = -11

Multiple Choice

What is the explicit formula for the arithmetic sequence 3, 11, 19, ...

• $$a_n=3+8\left(n-1\right)$$

• $$a_n=8+3\left(n-1\right)$$

• $$a_1=3;\ a_n=a_{n-1}+8$$

• $$a_n=-5+8\left(n-1\right)$$

​3, 11, 19,...

Multiple Choice

$$a_1=-2;\ a_n=a_{n-1}+9$$  What are the first five terms of the sequence given by

• -2, 7, 16, 25, 34

• 7, 16, 25, 34, 43

• -11, -2, 7, 16, 25

• 9, 7, 5, 3, 1

Multiple Choice

$$a_n=0.5+5n$$  

Given the explicit formula above, find the first term and the common difference.

• d = 5

  $$a_1=5.5$$  

• d = -5

  $$a_1=5.5$$  

• d = 5

  $$a_1=0.5$$  

• d = 0.5

  $$a_{1\ }=5$$  

Multiple Choice

Given an arithmetic sequence where the 22nd term is -15 and the common difference is 6, find the first term of the sequence.

• -15

• -141

• 6

• not enough information is given

​..., 7, _____, -3

​7 + d + d = -3

​2d + 7 = -3

​2d = -10

​d = -5

Poll

How do you feel about the quiz now?

• Bring it on-I'm ready!

• Feeling much more confident, but I will still review

• I need to practice more

• I'm still worried

​You Are Ready!!!

​This Quizizz is posted on google classroom if you would like to re-try it.