Question

find ∞
∑ 50(2x-1) ^ r-1
r=1

when x=0.3

Answer 1

the sum of a geometric series is:\[\frac{a}{1-r}\]

Answer 2

in this case: a = 50(.6-1)

Answer 3

.... and so does r I think

Answer 4

50(-.4)^(r-1)

a = 50 and r=-.4

i prolly shoulda used different letters so as not to confuse the original "r"

Answer 5

hmmm ok... but i dont think this is completed yet

Answer 6

since |-.4| < 1 this should converge

Answer 7

\[\frac{50}{1--.4}=\frac{50}{1.4}\]