Question

the sum of infinite terms of the progression 1+3x+5x²+7x³..........(x<1) is

Answer 1

Sn = 1 + 3x + 5x² + 7x³ + ............................
xSn =      x + 3x² + 5x³ + ............................
-            -    -       -
Sn(1-x) = 1 + 2x + 2x² + 2x³ .............
Sn(1-x) = 1 + 2x(1 + x + x² + x² + ...................................)
Sn(1-x) = 1 + 2x(1/(1-x))        (sum of infinite G.P.)
Sn(1-x) = (1+x)/(1-x)
Sn = (1+x)/(1-x)²      ( please re-check in case of any calculation error.)

Answer 2

Answer:

1/2

Step-by-step explanation:

sum is 6....................sum of 1st term=3

3/6=6.....go always with option it will save your time ..