Chú ý: Để đảm bảo quyền lợi và bảo vệ tài khoản của mình
Bạn hãy xác thực địa chỉ email đăng ký nhé. Chi tiết xem tại đây
Bạn hãy xác thực địa chỉ email đăng ký nhé. Chi tiết xem tại đây
{"common":{"save":0,"post_id":"6461","level":1,"total":10,"point":10,"point_extra":0},"segment":[{"id":"6892","mon_id":"1158767","chapter_id":"1158801","post_id":"6461","question":"<p>Cho tam th\u1ee9c <span class=\"math-tex\">$f(x)=ax^2+bx+c\\space\\space(a\\ne0),\\space\\Delta=b^2-4ac$<\/span>. Ta có <span class=\"math-tex\">$f(x)\\ge0,\\space\\forall x\\in\\mathbb{R}$<\/span> khi và ch\u1ec9 khi:<\/p>","options":["<strong>A. <span class=\"math-tex\">$\\begin{cases}a<0\\\\\\Delta\\le0 \\end{cases}$<\/span><\/strong>","<strong>B. <span class=\"math-tex\">$\\begin{cases}a\\le0\\\\\\Delta<0 \\end{cases}$<\/span><\/strong>","<strong>C. <span class=\"math-tex\">$\\begin{cases}a<0\\\\\\Delta\\ge0 \\end{cases}$<\/span><\/strong>","<strong>D. <span class=\"math-tex\">$\\begin{cases}a>0\\\\\\Delta\\le0 \\end{cases}$<\/span><\/strong>"],"correct":"4","level":"1","hint":"","answer":"<p>Áp d\u1ee5ng \u0111\u1ecbnh lý v\u1ec1 d\u1ea5u c\u1ee7a tam th\u1ee9c b\u1eadc hai ta có: <\/p><p><span class=\"math-tex\">$f(x)\\ge0,\\space\\forall x\\in\\mathbb{R}$<\/span> khi và ch\u1ec9 khi <strong><span class=\"math-tex\">$\\begin{cases}a>0\\\\\\Delta\\le0 \\end{cases}$<\/span>.<\/strong><\/p><p>Ch\u1ecdn<strong> <span style=\"color:#16a085;\">D. <span class=\"math-tex\">$\\begin{cases}a>0\\\\\\Delta\\le0 \\end{cases}$<\/span><\/span><\/strong><span style=\"color:#16a085;\"><strong>A. <span class=\"math-tex\">$\\begin{cases}a<0\\\\\\Delta\\le0 \\end{cases}$<\/span>B. <span class=\"math-tex\">$\\begin{cases}a\\le0\\\\\\Delta<0 \\end{cases}$<\/span>C. <span class=\"math-tex\">$\\begin{cases}a<0\\\\\\Delta\\ge0 \\end{cases}$<\/span><\/strong><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2023-05-30 05:38:29","option_type":"math","len":0},{"id":"6893","mon_id":"1158767","chapter_id":"1158801","post_id":"6461","question":"<p>Cho tam th\u1ee9c <span class=\"math-tex\">$f(x)=ax^2+bx+c\\space\\space(a\\ne0),\\space\\Delta=b^2-4ac$<\/span>. Ta có <span class=\"math-tex\">$f(x)>0,\\space\\forall x\\in\\mathbb{R}$<\/span> khi và ch\u1ec9 khi:<\/p>","options":["<strong>A. <span class=\"math-tex\">$\\begin{cases}a<0\\\\\\Delta\\le0 \\end{cases}$<\/span><\/strong>","<strong><span aria-label=\"math widget\" contenteditable=\"false\" role=\"region\" tabindex=\"-1\"><\/span>B. <span class=\"math-tex\">$\\begin{cases}a>0\\\\\\Delta<0 \\end{cases}$<\/span><\/strong>","<strong>C. <span class=\"math-tex\">$\\begin{cases}a<0\\\\\\Delta\\ge0 \\end{cases}$<\/span><\/strong>","<strong>D. <span class=\"math-tex\">$\\begin{cases}a>0\\\\\\Delta\\le0 \\end{cases}$<\/span><\/strong>"],"correct":"2","level":"1","hint":"","answer":"<p>Áp d\u1ee5ng \u0111\u1ecbnh lý v\u1ec1 d\u1ea5u c\u1ee7a tam th\u1ee9c b\u1eadc hai ta có: <\/p><p><span class=\"math-tex\">$f(x)>0,\\space\\forall x\\in\\mathbb{R}$<\/span> khi và ch\u1ec9 khi <strong><span class=\"math-tex\">$\\begin{cases}a>0\\\\\\Delta<0 \\end{cases}$<\/span>.<\/strong><\/p><p>Ch\u1ecdn<strong> <span style=\"color:#16a085;\">B. <span class=\"math-tex\">$\\begin{cases}a>0\\\\\\Delta<0 \\end{cases}$<\/span><\/span><\/strong><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2023-05-30 05:39:11","option_type":"math","len":0},{"id":"6895","mon_id":"1158767","chapter_id":"1158801","post_id":"6461","question":"<p>Cho tam th\u1ee9c <span class=\"math-tex\">$f(x)=ax^2+bx+c\\space\\space(a\\ne0),\\space\\Delta=b^2-4ac$<\/span>. Ta có <span class=\"math-tex\">$f(x)<0,\\space\\forall x\\in\\mathbb{R}$<\/span> khi và ch\u1ec9 khi:<\/p>","options":["<strong>A. <span class=\"math-tex\">$\\begin{cases}a<0\\\\\\Delta\\le0 \\end{cases}$<\/span> <\/strong>\u200b\u200b\u200b\u200b\u200b\u200b\u200b","<strong>B. <span class=\"math-tex\">$\\begin{cases}a<0\\\\\\Delta<0 \\end{cases}$<\/span><\/strong>","<strong>C. <span class=\"math-tex\">$\\begin{cases}a<0\\\\\\Delta\\ge0 \\end{cases}$<\/span><\/strong>","<strong>D. <span class=\"math-tex\">$\\begin{cases}a>0\\\\\\Delta\\le0 \\end{cases}$<\/span><\/strong>"],"correct":"2","level":"1","hint":"","answer":"<p>Áp d\u1ee5ng \u0111\u1ecbnh lý v\u1ec1 d\u1ea5u c\u1ee7a tam th\u1ee9c b\u1eadc hai ta có: <\/p><p><span class=\"math-tex\">$f(x)<0,\\space\\forall x\\in\\mathbb{R}$<\/span> khi và ch\u1ec9 khi <strong><span class=\"math-tex\">$\\begin{cases}a<0\\\\\\Delta<0 \\end{cases}$<\/span>.<\/strong><\/p><p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>B. <span class=\"math-tex\">$\\begin{cases}a<0\\\\\\Delta<0 \\end{cases}$<\/span><\/strong><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2023-05-30 05:44:40","option_type":"math","len":0}]}