{"common":{"save":0,"post_id":"7047","level":3,"total":10,"point":10,"point_extra":0},"segment":[{"id":"4836","post_id":"7047","mon_id":"1158924","chapter_id":"1159147","question":"<p>Trong các dãy s\u1ed1 <span class=\"math-tex\">$(u_n)$<\/span> cho b\u1edfi s\u1ed1 h\u1ea1ng t\u1ed5ng quát <span class=\"math-tex\">$u_n$<\/span> sau, dãy s\u1ed1 nào sau \u0111ây là dãy s\u1ed1 t\u0103ng?<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$u_n=\\dfrac{1}{2^n}$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$u_n=\\dfrac{1}{n}$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$u_n=n$<\/span>","<strong>D.<\/strong> <span class=\"math-tex\">$u_n=(-1)^n$<\/span>"],"correct":"3","level":"3","hint":"","answer":"<p>Dãy s\u1ed1 <span class=\"math-tex\">$(u_n)$<\/span> v\u1edbi <span class=\"math-tex\">$u_n=n$<\/span> là dãy các s\u1ed1 nguyên d\u01b0\u01a1ng t\u0103ng d\u1ea7n.<\/p><p>Ch\u1ecdn <span style=\"color:#16a085;\"> <strong>C.<\/strong> <span class=\"math-tex\">$u_n=n$<\/span> .<\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2023-12-03 04:06:36","option_type":"math","len":0},{"id":"4837","post_id":"7047","mon_id":"1158924","chapter_id":"1159147","question":"<p>Cho dãy s\u1ed1 <span class=\"math-tex\">$(u_n)$<\/span> v\u1edbi <span class=\"math-tex\">$u_n=n$<\/span> . Kh\u1eb3ng \u0111\u1ecbnh nào sau \u0111ây là <strong>sai<\/strong>?<\/p>","options":["<strong>A.<\/strong> N\u0103m s\u1ed1 h\u1ea1ng \u0111\u1ea7u c\u1ee7a dãy là 1; 2; 3; 4; 5.","<strong>B.<\/strong> B\u1ecb ch\u1eb7n trên b\u1edfi s\u1ed1 M = 0.","<strong>C.<\/strong> B\u1ecb ch\u1eb7n d\u01b0\u1edbi b\u1edfi s\u1ed1 M = 0.","<strong>D.<\/strong> Là dãy s\u1ed1 t\u0103ng."],"correct":"2","level":"3","hint":"","answer":"<p>Nh\u1eadn xét <span class=\"math-tex\">$u_n>0;\\forall n\\in N^*$<\/span> nên dãy s\u1ed1 b\u1ecb ch\u1eb7n d\u01b0\u1edbi b\u1edfi M = 0.<\/p><p>Câu sai là <span style=\"color:#16a085;\"><strong>B.<\/strong> B\u1ecb ch\u1eb7n trên b\u1edfi s\u1ed1 M = 0.<\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2023-12-03 04:14:02","option_type":"txt","len":3},{"id":"4839","post_id":"7047","mon_id":"1158924","chapter_id":"1159147","question":"<p>Cho dãy s\u1ed1 <span class=\"math-tex\">$(u_n)$<\/span> v\u1edbi <span class=\"math-tex\">$u_n=\\dfrac{1}{n^2+n}$<\/span> . Kh\u1eb3ng \u0111\u1ecbnh nào sau \u0111ây là <strong>sai<\/strong>?<\/p>","options":["<strong>A.<\/strong> 5 s\u1ed1 h\u1ea1ng \u0111\u1ea7u tiên c\u1ee7a dãy là <span class=\"math-tex\">$\\dfrac{1}{2};\\dfrac{1}{6};\\dfrac{1}{12};\\dfrac{1}{20};\\dfrac{1}{30}$<\/span> .","<strong>B.<\/strong> Là dãy s\u1ed1 t\u0103ng.","<strong>C.<\/strong> B\u1ecb ch\u1eb7n trên b\u1edfi s\u1ed1 M = <span class=\"math-tex\">$\\dfrac{1}{2}$<\/span>","<strong>D.<\/strong> Không b\u1ecb ch\u1eb7n."],"correct":"2","level":"3","hint":"","answer":"<p>Ta có <span class=\"math-tex\">$u_1=\\dfrac{1}{2};u_2=\\dfrac{1}{6}$<\/span> nên <span class=\"math-tex\">$u_1>u_2$<\/span> . V\u1eady <span class=\"math-tex\">$(u_n)$<\/span> không là dãy t\u0103ng.<\/p><p>Câu sai là <span style=\"color:#16a085;\"><strong>B.<\/strong> Là dãy s\u1ed1 t\u0103ng.<\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2023-12-03 04:24:09","option_type":"math","len":0}]}