Question

the first term of gp is 4 while its sum to infinity is 5. find the sum of 8 terms​

Answer 1

Answer:

Given:-

S∞=5

a=x

As we know that,

S∞=1−ra

∴1−rx=5

⇒5x=1−r

⇒r=1−5x

Now,

∣r∣<1

∣∣∣∣∣∣1−5x∣∣∣∣∣∣<1

⇒−1<1−5x<1

⇒−2<5−x<0

⇒0<5x<2

⇒0<x<10