Qwertyuiop[]
Junior Member
- Joined
- Jun 1, 2022
- Messages
- 123
∑k=12n(k2n)2−2k32n−k, i want to express this sum in binomial form but the problem is instead of (n choose k), i have (2n choose k) and the powers of coefficients are not n-k and k. Using the laws of indices i can factor out 2^-2 from 2^(-2k) to get 2−2∑k=12n(k2n)2k32n−k But i can't rewrite 3^(2n-k) to 3^(n-k), I just need a hint.