so sánh 2 phân số 2020^2019 +1 / 2020^2020 – 1 và 2020^2018+1 / 2020^2019 -1 15/11/2021 Bởi Aubrey so sánh 2 phân số 2020^2019 +1 / 2020^2020 – 1 và 2020^2018+1 / 2020^2019 -1
Đặt M = 2020^2019+1/2020^2020-1 => 2020M = 2020^2020+2020/2020^2020-1 = 2020^2020-1+2021/2020^2020-1 = 1 + 2021/2020^2020-1 Đặt N = 2020^2018+1/2020^2019-1 => 2020N = 2020^2019+2020/2020^2019-1 = 2020^2019-1+2021/2020^2019-1 = 1 + 2021/2020^2019-1 Vì 2021/2020^2020-1 < 2021/2020^2019-1 nên 1 + 2021/2020^2020-1 < 1 + 2021/2020^2019-1 => 2020M > 2020N hay M > N Vậy M > N. HỌC TỐT! Bình luận
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Đặt M = 2020^2019+1/2020^2020-1
=> 2020M = 2020^2020+2020/2020^2020-1 = 2020^2020-1+2021/2020^2020-1 = 1 + 2021/2020^2020-1
Đặt N = 2020^2018+1/2020^2019-1
=> 2020N = 2020^2019+2020/2020^2019-1 = 2020^2019-1+2021/2020^2019-1 = 1 + 2021/2020^2019-1
Vì 2021/2020^2020-1 < 2021/2020^2019-1 nên 1 + 2021/2020^2020-1 < 1 + 2021/2020^2019-1
=> 2020M > 2020N
hay M > N
Vậy M > N.
HỌC TỐT!