Chú ý: Để đảm bảo quyền lợi và bảo vệ tài khoản của mình
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{"common":{"save":0,"post_id":"6194","level":2,"total":10,"point":10,"point_extra":0},"segment":[{"id":"5499","mon_id":"1158767","chapter_id":"1158770","post_id":"6194","question":"<p>Trong các t\u1eadp h\u1ee3p sau, t\u1eadp h\u1ee3p nào có \u0111úng hai t\u1eadp h\u1ee3p con?<\/p>","options":["<strong>A.<\/strong> { x; y }","<strong>B.<\/strong> { Ø ; x }","<strong>C.<\/strong> { x }","<strong>D.<\/strong> { x ; y ; Ø }"],"correct":"3","level":"2","hint":"","answer":"<p>T\u1eadp h\u1ee3p { x } có hai t\u1eadp h\u1ee3p con là t\u1eadp Ø và { x }.<\/p><p>\u0110áp án là <span style=\"color:#16a085;\"><strong>C.<\/strong> { x }<\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2022-09-11 10:34:45","option_type":"txt","len":2},{"id":"5500","mon_id":"1158767","chapter_id":"1158770","post_id":"6194","question":"<p>Cách vi\u1ebft nào sau \u0111ây <b>\u0111úng<\/b>?<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$a\\subset[a;b]$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$\\{a\\}\\subset[a;b]$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$\\{a\\}\\in[a;b]$<\/span>","<strong>D. <\/strong><span class=\"math-tex\">$a\\subset(a;b]$<\/span>"],"correct":"2","level":"2","hint":"<p>Ta dùng kí hi\u1ec7u ∈ và ∉ \u0111\u1ec3 ch\u1ec9 m\u1ed1i quan h\u1ec7 gi\u1eefa ph\u1ea7n t\u1eed và t\u1eadp h\u1ee3p.<\/p><p>Ta dùng kí hi\u1ec7u ⊂ và <span class=\"math-tex\">$\\not\\subset$<\/span> \u0111\u1ec3 ch\u1ec9 m\u1ed1i quan h\u1ec7 gi\u1eefa hai t\u1eadp h\u1ee3p.<\/p>","answer":"<p><strong>A.<\/strong> <span class=\"math-tex\">$a\\subset[a;b]$<\/span> (<span style=\"color:#e74c3c;\">sai <\/span>vì <span class=\"math-tex\">$a$<\/span> là ph\u1ea7n t\u1eed, còn <span class=\"math-tex\">$[a;b]$<\/span> là t\u1eadp h\u1ee3p)<\/p><p><strong>B.<\/strong> <span class=\"math-tex\">$\\{a\\}\\subset[a;b]$<\/span> (<span style=\"color:#16a085;\">\u0111úng<\/span>)<\/p><p><strong>C.<\/strong> <span class=\"math-tex\">$\\{a\\}\\in[a;b]$<\/span> (<span style=\"color:#e74c3c;\">sai <\/span>vì <span class=\"math-tex\">$\\{a\\}$<\/span> và <span class=\"math-tex\">$[a;b]$<\/span> là t\u1eadp h\u1ee3p)<\/p><p><strong>D. <\/strong><span class=\"math-tex\">$a\\subset(a;b]$<\/span> (<span style=\"color:#e74c3c;\">sai <\/span>vì <span class=\"math-tex\">$a$<\/span> là ph\u1ea7n t\u1eed, còn <span class=\"math-tex\">$(a;b]$<\/span> là t\u1eadp h\u1ee3p)<\/p><p>\u0110áp án \u0111úng là <span style=\"color:#16a085;\"><strong>B.<\/strong> <span class=\"math-tex\">$\\{a\\}\\subset[a;b]$<\/span><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2022-09-11 10:44:32","option_type":"math","len":0},{"id":"5501","mon_id":"1158767","chapter_id":"1158770","post_id":"6194","question":"<p>G\u1ecdi <span class=\"math-tex\">$B_n$<\/span> là t\u1eadp h\u1ee3p các b\u1ed9i s\u1ed1 c\u1ee7a <span class=\"math-tex\">$n$<\/span> trong <span class=\"math-tex\">$\\mathbb{N}$<\/span>. Xác \u0111\u1ecbnh t\u1eadp h\u1ee3p <span class=\"math-tex\">$B_2\\cap B_4$<\/span>.<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$B_4$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$B_8$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$\\varnothing $<\/span>","<strong>D. <\/strong><span class=\"math-tex\">$B_2$<\/span>"],"correct":"1","level":"2","hint":"<p>Giao c\u1ee7a hai t\u1eadp h\u1ee3p g\u1ed3m các ph\u1ea7n t\u1eed thu\u1ed9c c\u1ea3 hai t\u1eadp h\u1ee3p \u0111ó.<\/p><p>A ∩ B = { x | x ∈ A và x ∈ B }<\/p>","answer":"<p>Ta có:<\/p><p><span class=\"math-tex\">$B_2=\\{2k|k\\in\\mathbb{N}\\}=\\{0;2;4;6;8;10;12;...\\}$<\/span><\/p><p><span class=\"math-tex\">$B_4=\\{4k|k\\in\\mathbb{N}\\}=\\{0;4;8;12;16...\\}$<\/span><\/p><p>Suy ra <span class=\"math-tex\">$B_2\\cap B_4=\\{0;4;8;12;16;..\\}=B_4$<\/span><\/p><p>\u0110áp án là <span style=\"color:#16a085;\"><strong>A.<\/strong> <span class=\"math-tex\">$B_4$<\/span><\/span><\/p>","type":"choose","extra_type":"shape2","user_id":"131","test":"0","date":"2022-09-11 10:56:24","option_type":"math","len":0}]}