The solution shows 10 terms, whereas your statement of the problem shows 12 terms. In other words, your problem statement shows an extra ∑(10,11). Resolve that dichotomy first, then we can continue.
The solution shows 10 terms, whereas your statement of the problem shows 12 terms. In other words, your problem statement shows an extra (10,11). Resolve that dichotomy first, then we can continue.
Ratch