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Section Solutions

Sequences

  1. Write the first five terms of the sequence in simplest form.

    1. 113,93,73,53,…

    2. 1,√22,0,βˆ’βˆš22,βˆ’1,…

    3. 52,114,298,…

  2. Write a formula for each sequence. I.e. xn=___ for n=1,2,3,….

    1. xn=3n5nβ‹―

    2. (βˆ’1)nβ‹―

    3. (βˆ’1)n+1nn+1β‹―

  3. What is the least upper bound and the greatest lower bound? Prove it.

    1. GLB = 0, LUB = 2

    2. GLB = 2/3 , LUB = 9/7

  4. Is the sequence monotonic or not? Prove it.

    1. decreasing

    2. not monotonic

    3. increasing

  5. Use limits to find whether or not the sequence converges.

    1. converges to 0

    2. converges to 1

    3. converges to 0

    4. converges to eβˆ’1

  6. N = 3001

  7. N = the first positive integer larger than 32Ο΅

Series

  1. List, in simplest form, the first three partial sums for the series and write a formula for the Nth partial sum.

    1. 1,43,139,4027,…,Sn=1βˆ’3n+11βˆ’313n=1βˆ’(13)n+11βˆ’13

    2. 3,365,33125,…,Sn=31βˆ’5n+1(1βˆ’5)5n=31βˆ’(15)n+11βˆ’15

  2. What does the geometric series converge to?

    1. 1

    2. 9

  3. βˆžβˆ‘n=353n=53βˆžβˆ‘n=31n>βˆžβˆ‘n=31n which diverges

  4. Apply the integral test to determine if the series converges.

    1. converges

    2. diverges

  5. Determine if these series converge via one of the nth term test, integral test, p-series test, comparison test, or limit comparison test.

    1. converges by limit comparison with 1n2

    2. converges by limit comparison with 1n2

    3. diverges, nth term test

    4. converges, geometric series

    5. diverges, nth term test

    6. separate the two series, one harmonic (diverges), one geometric (converges)

    7. separate the two series, both geometric (converges)

    8. separate the two series, one constant (diverges by nth term test), one converges by integral or p-series test

    9. limit comparison with 1n2

    10. converges, geometric series

    11. limit comparison with 1n3

    12. limit comparison with 1√n

    13. converges by limit comparison with 1n2

    14. converges by comparison to 1n2

    15. converges by limit comparison with 1n

    16. converges by comparison to 1n2

    17. converges by comparison to 1n2

    18. converges by limit comparison with 13n

    19. converges by comparison to 1n2

    20. converges, integral test

  6. Determine whether the alternating series is convergent or divergent.

    1. converges

    2. converges

    3. diverges, terms don't tend to zero

    4. diverges, rewrite it so that you can see that an=(5/3)n

    5. converges

    6. converges

    7. diverges

    8. diverges

    9. converges

    10. converges

    11. diverges, terms don't tend to zero

    12. converges, rewrite it without a trig function

  7. Conditionally Convergent, Absolutely Convergent, or Divergent?

    1. D

    2. CC

    3. AC, to get absolutely convergent, convert log4 to ln and use integral test

    4. AC

    5. D

    6. AC, ratio test + that clever natural log trick for limits

    7. D

    8. CC

    9. AC

    10. CC

    11. this is a neat problem

    12. this is a really neat problem

  8. Intervals of convergence.

    1. (βˆ’1,1)

    2. (βˆ’4,4)

    3. (βˆ’1/3,1/3)

    4. (2,8)

    5. (βˆ’1,1)

    6. (βˆ’1,1)

    7. no interval, diverges for all xβ‰ βˆ’3

    8. no interval, diverges for all x≠0

    9. (βˆ’8,0)

    10. (βˆ’1,1)

    11. this is a neat problem

    12. (1,3)

  9. Taylor Series (just the first few terms)

    1. βˆ’1+2(xβˆ’1)βˆ’3(xβˆ’1)2+4(xβˆ’1)3βˆ’5(xβˆ’1)4+6(xβˆ’1)5

    2. 2xβˆ’8x3/3!+32x5/5!βˆ’128x7/7!…

    3. 3+3ln(3)(xβˆ’1)+32(ln(3))2(xβˆ’1)2+12(ln(3))3(xβˆ’1)3+18(ln(3))4(xβˆ’1)4+ 140(ln(3))5(xβˆ’1)5

    4. e2+e2(xβˆ’2)+12e2(xβˆ’2)2+16e2(xβˆ’2)3+124e2(xβˆ’2)4+1120e2(xβˆ’2)5

    5. βˆ’x+Ο€2+16(xβˆ’Ο€2)3βˆ’1120(xβˆ’Ο€2)5

    6. xβˆ’12x2+13x3βˆ’14x4+15x5

  10. Use multiplication, substitution, differentiation, and integration whenever possible to find a series representation of each of the following functions.

    1. βˆžβˆ‘n=0(βˆ’1)nx2(n+1)(2n)!

    2. βˆžβˆ‘n=0(βˆ’1)nx4n+1(2n+1)!

    3. 5βˆžβˆ‘n=03nn!xn+1

    4. 2βˆžβˆ‘n=0(nβˆ’1)rn You know the series for 11βˆ’r.