Trả lời:
Giải bởi Vietjack
a) P = 1 – 2 + 22 – 23 +...+ 22022
2P = 2 – 22 + 23 – 24 +...+ 22023
Suy ra P + 2P = (1 – 2 + 22 – 23 +...+ 22022) + (2 – 22 + 23 – 24 +...+ 22023)
Hay 3P = 1 + (–2 + 2) + (22 – 22) + (–23 + 23) +...+ (22022 – 22022) + 22023
3P = 1 + 0 + 0 + 0 +...+ 0 + 22023
3P = 1 + 22023
Vậy .
a) P = 1 – 2 + 22 – 23 +...+ 22022
2P = 2 – 22 + 23 – 24 +...+ 22023
Suy ra P + 2P = (1 – 2 + 22 – 23 +...+ 22022) + (2 – 22 + 23 – 24 +...+ 22023)
Hay 3P = 1 + (–2 + 2) + (22 – 22) + (–23 + 23) +...+ (22022 – 22022) + 22023
3P = 1 + 0 + 0 + 0 +...+ 0 + 22023
3P = 1 + 22023
Vậy .