Answer :
The common ratio with the range
−
1<r< 1
the formula is
S=a11−r
We will use this formula because,
r=12
Sum
S=a11−r=21−12=4
God bless....I hope the explanation is useful...
The common ratio with the range
−
1<r< 1
the formula is
S=a11−r
We will use this formula because,
r=12
Sum
S=a11−r=21−12=4
God bless....I hope the explanation is useful...