phoenix159
Member
- Joined
- May 19, 2013
- Messages
- 79
- Gender
- Male
- HSC
- 2014
Find the sum of the first n terms of Tr = 2r + 2r - 1 (its the sum of an arithmetic and geometric series)
I got n2 - n/2 + 2n+1 - 2
But the textbook says n2 + 2n+1 - 2
I got n2 - n/2 + 2n+1 - 2
But the textbook says n2 + 2n+1 - 2