Find a1 in a geometric series for which Sn = 300, r = -3, and n = 4

1 answer

S(n) = a( r^n - 1)/(r-1)
a( (-3)^4 - 1)/(-3-1) = 300
a( 80 )/(-4) = 300
-20a = 300
a = -15

check:
first 4 terms would be -15 , +45, - 135, + 405
and -15 + 45 - 135 + 405 = 300
Similar Questions
  1. 1)Find a1 in a geometric series for which Sn=300,r=-3,and n=4A)15 B)15/2 C)-15 D)1/15 I chose A 2)Find the sum of the infinite
    1. answers icon 3 answers
  2. 1)Find a1 in a geometric series for which Sn=300,r=-3,and n=4A)15 B)15/2 C)-15 D)1/15 I chose A 2)Find the sum of the infinite
    1. answers icon 2 answers
  3. Consider the infinite geometric series below.a. Write the first 4 terms of the series b. Does the series diverge or converge? c.
    1. answers icon 1 answer
  4. Consider the infinite geometric seriesn=1 infinity symbol -4(2/3)^n-1 a. Write the first four terms of the series. b. Does the
    1. answers icon 1 answer
more similar questions