Dãy số nào sau đây giảm?
A. \({u_n} = \frac{{n - 5}}{{4n + 1}}\,\left( {n \in {\mathbb{N}^*}} \right)\)
B.\({u_n} = \frac{{5 - 3n}}{{2n + 3}}\,\left( {n \in {\mathbb{N}^*}} \right)\)
C. \({u_n} = 2{n^3} + 3\,\left( {n \in {\mathbb{N}^*}} \right)\)
D. \({u_n} = c{\rm{os}}\left( {2n + 1} \right)\,\left( {n \in {\mathbb{N}^*}} \right)\)
A. \({u_n} = \frac{{n - 5}}{{4n + 1}}\,\left( {n \in {\mathbb{N}^*}} \right)\)
B.\({u_n} = \frac{{5 - 3n}}{{2n + 3}}\,\left( {n \in {\mathbb{N}^*}} \right)\)
C. \({u_n} = 2{n^3} + 3\,\left( {n \in {\mathbb{N}^*}} \right)\)
D. \({u_n} = c{\rm{os}}\left( {2n + 1} \right)\,\left( {n \in {\mathbb{N}^*}} \right)\)
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Hóa Học lớp 12
