IB Maths AA HL | sequence and series | Geometric progression |

A geometric progression has first term u1 = a and common ratio r.



The sum to infinity of the geometric progression is begin mathsize 16px style 8 over 5 end style

The sum to infinity of the even-numbered terms open parentheses u subscript 2 plus u subscript 4 plus u subscript 6 plus midline horizontal ellipsis close parentheses is begin mathsize 16px style 3 over 5 end style



What is the value of a + r ?

[ligablumfelde]

I really liked this strategy but the problem is that you did this in 7 minutes (i understand explaining takes time but still doubt one can do this under 2 minutes)