7/29/2019 Arithmetic Seq and Series class assignment ANSWERS and HINTS

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Please show ALL WORK / STEPS for full marks on your assignment!

1. (a) Arithmetic, = (Each term goes up by 4, remember = )Only first answer provided here!

2. a) matches to C b) matches to D c) matches to E d) matches to B and e) matches to A

3. Start with = 1 + ( 1), then simplify to = + . (show steps)Then, use your simplified form to solve for when = 102. ( = )

4. First, set up a general term expression ( = 1 + ( 1)) given that 1 is given as 5. But since we dont know, let = 17, = 4.and solve for .

Once you have the general term, substitute = 10 to find the 10 term.

Second #4:Backside (a) 2 = 4 + 10 = 14. Similarly, 3 = 30. (b) Use formula to determine that 21 = 1344.

(c) First, use = 1 + ( 1) to find the 21st term. THEN, use formula to get the same sum, 21 = 1344.

(Note that in formula is simply the last term being added)

5. First use = 1 + ( 1) to determine . (The number of terms were adding)Then, use formula to find . Then again using formula. (Should get the same answer of-672!)

6. Use formula, since we dont know the last term were adding, . Answer: 7. We arent given 1 or ! However, we are given2, and we know that 3 = 2 + , 4 = 2 + 2, and

5 = 2 + 3. (That is, the fifth term is the second term plus some unknown added three times) Set up

and equation and solve for , then use sum formula to determine that 25 = .

8. Algebraic solution is.rather complex! (Ill show you in class) But you can reason this out / use guess andtest. Think of all the ways 2 (the sum of two unknown numbers) can add to 13. (What are the options for the

first two terms?) For each option, determine a value, and see if4 works out correctly. Then, determine 6

using formula.

9. (a) Series is 240 + 250 + 260 + + 300(b) Use formula to determine an expression for the sum, in terms of.

(c) Use the formula determined in (b) to find the sum of1890.

(d) Well discuss in-class, what do you think??

=

= 40 36 or 44 40 or 48 44