Math

posted by .

Find the no. of terms
1. 3,5,7...33
2.-5,-1,3,...75

Solve each problem.
1. In the Arithmetic sequence 5,8,11,14.... what is n if a sub n is 32?
2.Find the sum of the first 20 terms of the arithmetic sequence -15,-7,31,43...

  • Math -

    1. term(n) = a+(n-1)d
    you have a = 3, d = 2 , n = ??
    33 = 3 + (n-1)(2)
    30 = 2n - 2
    28 = 2n
    n = 14 ------ there are 14 terms

    do the 2nd one the same way

    for the other two, I don't know how you defined a sub n

    for the last:
    first find the number of terms in the same way I showed you
    you have a = -15 , d = 12 , n = ?
    once you find a and d
    use
    Sum(n) = (n/2)(2a + (n-1)(d) )

  • Math -

    Thank you so much . 1. In the Arithmetic sequence 5,8,11,14.... what is n if an is 32?
    1. In the Arithmetic sequence 5,8,11,14.... what is n if n is 32?

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Math *URGENT

    Please give the answers and solutions for each. 1.If the second term is 2 and the seventh term of a geometric sequence is 64, find the 12th term. 2. Which term if the geometric sequence 18,54,162,486,... is 3,188,646?
  2. Can someone help me?!

    The 1st, 5th and 13th terms of an arithmetic sequence are the first three terms of a geometric sequence with a common ratio 2. If the 21st term of the arithmetic sequence is 72, calculate the sum of the first 10 terms of the geometric …
  3. Maths

    1..The first 2 terms of a geometric progression are the same as the first two terms of an arithmetic progression.The first term is 12 and is greater than the second term.The sum of the first 3 terms od the arithmetic progression is …
  4. Algebra

    Determine whether each sequence is arithmetic or geometric. Find the next three terms. 14, 19, 24, 29, . . . A.geometric, 34, 39, 44 B.arithmetic, 32, 36, 41 C.arithmetic, 34, 39, 44 D.The sequence is neither geometric nor arithmetic. …
  5. Arithmetic Sequence Help!

    The sum of 3 consecutive terms of an arithmetic sequence is 165. The second of these terms is 11 times the first. Find the 3 terms From what I gathered: S(3) = 165 t(2)= 11(t1) The given formulas are: Sn= n/2[2a+(n-1)d] and tn=a+(n-1)d …
  6. math

    Determine whether each sequence is arithmetic or geometric. Find the next three terms. 1. 14, 19, 24, 29, . . . (1 point) geometric, 34, 39, 44 arithmetic, 32, 36, 41 arithmetic, 34, 39, 44 *** The sequence is neither geometric nor …
  7. math

    in an arithmetic sequence the common difference is equal to 2.the first term is also the first term of a geometric sequence. the sum of the first 3 terms of an arithmetic sequence and the sum of the first 9 terms of an arithmetic sequence …
  8. Math Help!!!

    determine whether each sequence is arithmetic or geometric. find the next three terms. 1. 14,19,24,29.... geometric, 34,39,44 arithmetic,32,36,41 arithmetic 34,39,44**** the sequence is nether geometric nor arithmetic 2. -4,8,-16,32.... …
  9. math

    in an arithmetic sequence whose first term is 4, the 1st, 3rd and 7th terms form consecutive terms of geometric sequence, find the sum of the first three terms of the arithmetic sequence
  10. Arithmetic sequence

    Three consecutive terms of an arithmetic sequence have a sum of 12 and a product of -80 .Find the terms. [hint : let the terms be x - d, x and x + d . ]

More Similar Questions