1+(-2)+(-3)+4+5+(-6)+(-7)+8+9+...+(-2021)+(-2022) Tham khảo câu trả lời từ Trợ lý ảo Lazi To find the sum of the given sequence, we can group the positive and negative terms separately. Grouping the positive terms: 4 + 5 + 8 + 9 + ... + 2020 + 2021 + 2022 This is an arithmetic sequence with a common difference of 1. We can use the formula for the sum of an arithmetic sequence: Sn = (n/2)(2a + (n-1)d) where Sn is the sum of the sequence, n is the number of terms, a is the first term, and d is the common difference. In this case, a = 4, d = 1, and the last term is 2022. We need to find the number of terms, n. 2022 = 4 + (n-1)(1) 2022 - 4 = n - 1 2018 = n - 1 2019 = n Now we can substitute these values into the formula: Sn = (n/2)(2a + (n-1)d) Sn = (2019/2)(2(4) + (2019-1)(1)) Sn = (2019/2)(8 + 2018) Sn = (2019/2)(2026) Sn = 2043237 So the sum of the positive terms is 2,043,237. Grouping the negative terms: -2 + (-3) + (-6) + (-7) + ... + (-2020) + (-2021) + (-2022) This is also an arithmetic sequence with a common difference of -1. We can use the same formula to find the sum. In this case, a = -2, d = -1, and the last term is -2022. We need to find the number of terms, n. -2022 = -2 + (n-1)(-1) -2022 + 2 = n - 1 -2020 = n - 1 -2019 = n Now we can substitute these values into the formula: Sn = (n/2)(2a + (n-1)d) Sn = (-2019/2)(2(-2) + (-2019-1)(-1)) Sn = (-2019/2)(-4 + 2020) Sn = (-2019/2)(2016) Sn = -2031612 So the sum of the negative terms is -2,031,612. Finally, we can find the sum of the entire sequence by adding the sums of the positive and negative terms: 2,043,237 + (-2,031,612) = 11,625 Therefore, the sum of the given sequence is 11,625.