limn→0 1−1221−132⋯1−1n21−121−13…1−1n is equal to
−12
12
2
-2
limn→0 1−1221−132⋯1−1n21−121−13…1−1n=limn→0 1+121+13…1+1n1−121−13…1−1n1−121−13⋯1−1n=limn→0 32×43×…×n+1n=limn→0 n+12=12