Question 19

Jambmaths question: 

Find to infinity, the sum of the sequence $1,\tfrac{9}{10},{{(\tfrac{9}{10})}^{2}},{{(\tfrac{9}{10})}^{3}}\cdot \cdot \cdot $

Jamb Maths Solution: 

a =1, r= $\tfrac{9}{10}$

${{S}_{\infty }}=\frac{a}{1-r}=\frac{1}{1-\tfrac{9}{10}}=\frac{1}{\tfrac{10-9}{10}}=\frac{1}{\tfrac{1}{10}}=1\div \tfrac{1}{10}=1\times 10=10$

Jamb Maths Topic: 
Sequence and Series
Year of Exam: 
Jamb Maths 2009