maths

posted by .

find the sum of the infinite series (2/9)^2-(2/9)^3+(2/9)^4-(2/9)^5+ ...

  • maths -

    (2/9)^2-(2/9)^3+(2/9)^4-(2/9)^5+
    This is like a geometric series with the first terms missing
    1 -1(2/9)^1 +1(2/9)^2-1(2/9)^3+(2/9)^4-(2/9)^5+
    so if we find the sum of that series and subtract [1 -1(2/9)^1], we have it
    so
    g = 1
    r = -2/9
    in Sn = g (1-r^n)/(1-r)
    n is infinite and |r| < 1
    so Sn =g/(1-r)
    Sn = 1/(1-2/9) = 1.286
    so we want
    1.286 -[1-2/9]
    .508

  • maths -

    i need help

  • maths -

    Whoa - typo
    Sn = 1/(1+2/9) because r = -2/9
    Sn = .818
    so we want
    .818 -[1-2/9]
    .040

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. algebra

    1)Find a1 in a geometric series for which Sn=300,r=-3,and n=4 a.15 b.15/2 c.-15 d.1/15 answer=a 2)Find the sum of the infinite geometric series n=1 at the bottom of the sigma notation 20(-1/4)n-1 on the right side a.25 b.80/3 c.16 …
  2. algebra(check)

    1)Find a1 in a geometric series for which Sn=300,r=-3,and n=4 a.15 b.15/2 c.-15 d.1/15 answer=a 2)Find the sum of the infinite geometric series n=1 at the bottom of the sigma notation 20(-1/4)n-1 on the right side a.25 b.80/3 c.16 …
  3. algebra

    1)Find a1 in a geometric series for which Sn=300,r=-3,and n=4 a.15 b.15/2 c.-15 d.1/15 answer=a 2)Find the sum of the infinite geometric series n=1 at the bottom of the sigma notation 20(-1/4)n-1 on the right side a.25 b.80/3 c.16 …
  4. algebra

    1)Find a1 in a geometric series for which Sn=300,r=-3,and n=4 a.15 b.15/2 c.-15 d.1/15 answer=a 2)Find the sum of the infinite geometric series n=1 at the bottom of the sigma notation 20(-1/4)n-1 on the right side a.25 b.80/3 c.16 …
  5. math

    1)Find a1 in a geometric series for which Sn=300,r=-3,and n=4 A)15 B)15/2 C)-15 D)1/15 I chose A 2)Find the sum of the infinite geometric series. Sigma sign with infinity symbol above and n=1 below. To the right 20(-1/4)n-1 A)25 B)80/3 …
  6. math(need 2nd opinion)

    1)Find a1 in a geometric series for which Sn=300,r=-3,and n=4 A)15 B)15/2 C)-15 D)1/15 I chose A 2)Find the sum of the infinite geometric series. Sigma sign with infinity symbol above and n=1 below. To the right 20(-1/4)n-1 A)25 B)80/3 …
  7. calculus

    Consider the infinite series of the form: (+/-)3(+/-)1(+/-)(1/3)(+/-)(1/9)(+/-)(1/27)(+/-)...(+/-)(1/3^n)(+/-)... (A) Find x and y from: x(</=)(+/-)3(+/-)1(+/-)(1/3)(+/-)...(</=)y. (B) Can you choose the signs to make the series …
  8. calculus

    Consider the infinite series of the form: (+/-)3(+/-)1(+/-)(1/3)(+/-)(1/9)(+/-)(1/27)(+/-)...(+/-)(1/3^n)(+/-)... (A) Find x and y from: x(</=)(+/-)3(+/-)1(+/-)(1/3)(+/-)...(</=)y. (B) Can you choose the signs to make the series …
  9. Pre-Calculus

    Q.Determine the sum of each infinite geometric series. t_1= 8 r = -2^1/2 ---------------------------------------- A.This is a divergent series because the absolute value of r is greater than 1. ---------------------------------------- …
  10. help maths partail sum

    find the partial sum and the limiting sum of the following infinite series 1/4+1/10+4/18.... show step got no ideal at all

More Similar Questions