{"common":{"save":0,"post_id":"7552","level":3,"total":10,"point":10,"point_extra":0},"segment":[{"id":"5512","post_id":"7552","mon_id":"1159285","chapter_id":"1159288","question":"<p>Tìm t\u1ea5t c\u1ea3 các giá tr\u1ecb th\u1ef1c c\u1ee7a tham s\u1ed1 m \u0111\u1ec3 hàm s\u1ed1 <span class=\"math-tex\">$y=\\dfrac{2}{3}x^3+(m-1)x^2+(m^2-4m+3)x-1$<\/span> có hai \u0111i\u1ec3m c\u1ef1c tr\u1ecb.<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$-5< m<-1$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$1< m<5$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$-5< m <1$<\/span>","<strong>D.<\/strong> <span class=\"math-tex\">$-1 < m < 5$<\/span>"],"correct":"2","level":"3","hint":"<p>S\u1eed d\u1ee5ng c\u1ef1c tr\u1ecb c\u1ee7a hàm s\u1ed1.<\/p>","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>B.<\/strong> <span class=\"math-tex\">$1< m<5$<\/span>.<\/span><\/p><p>Ta có <span class=\"math-tex\">$y^\\prime=2x^2+2(m-1)x+m^2-4m+3$<\/span>.<\/p><p>Hàm s\u1ed1 \u0111ã cho có hai \u0111i\u1ec3m c\u1ef1c tr\u1ecb khi và ch\u1ec9 khi ph\u01b0\u01a1ng trình <span class=\"math-tex\">$y^\\prime=0$<\/span> có hai nghi\u1ec7m phân bi\u1ec7t.<\/p><p>⇔ <span class=\"math-tex\">$\\Delta^\\prime=(m-1)^2-2(m^2-4m+3) > 0$<\/span> <\/p><p>⇔ <span class=\"math-tex\">$-m^2+6m-5>0$<\/span><\/p><p>⇔ 1 < m < 5.<\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2024-08-11 04:27:17","option_type":"math","len":0},{"id":"5513","post_id":"7552","mon_id":"1159285","chapter_id":"1159288","question":"<p>Có bao nhiêu giá tr\u1ecb nguyên c\u1ee7a tham s\u1ed1 m \u0111\u1ec3 hàm s\u1ed1 <span class=\"math-tex\">$y=\\dfrac{2x+4}{x-m}$<\/span> \u0111\u1ed3ng bi\u1ebfn trên kho\u1ea3ng <span class=\"math-tex\">$(-\\infty;-4)$<\/span>?<\/p>","options":["<strong>A.<\/strong> 1","<strong>B.<\/strong> 3","<strong>C.<\/strong> 4","<strong>D.<\/strong> 2"],"correct":"4","level":"3","hint":"<p>S\u1eed d\u1ee5ng hàm s\u1ed1 \u0111\u1ed3ng bi\u1ebfn.<\/p>","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>D.<\/strong> 2.<\/span><\/p><p>Hàm s\u1ed1 xác \u0111\u1ecbnh trên <span class=\"math-tex\">$(-\\infty;-4)$<\/span> khi <span class=\"math-tex\">$m\\ge-4$<\/span> (1).<\/p><p><span class=\"math-tex\">$y^\\prime=\\dfrac{-2m-4}{(x-m)^2}$<\/span>, v\u1edbi m\u1ecdi x <span class=\"math-tex\">$\\ne$<\/span> m.<\/p><p>Hàm s\u1ed1 \u0111\u1ed3ng bi\u1ebfn trên <span class=\"math-tex\">$(-\\infty;-4)$<\/span> khi <span class=\"math-tex\">$y^\\prime >0$<\/span> v\u1edbi m\u1ecdi x ∈ <span class=\"math-tex\">$(-\\infty;-4)$<\/span> <br \/>⇔ <span class=\"math-tex\">$-2m-4>0$<\/span> ⇔ m < –2 (2).<\/p><p>T\u1eeb (1) và (2) suy ra: <span class=\"math-tex\">$-4\\le m<-2$<\/span>. Vì m ∈ \u2124 nên m = –3 ho\u1eb7c m = –4.<\/p><p>V\u1eady có 2 giá tr\u1ecb nguyên c\u1ee7a m th\u1ecfa yêu c\u1ea7u.<\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2024-08-11 04:33:56","option_type":"txt","len":0},{"id":"5514","post_id":"7552","mon_id":"1159285","chapter_id":"1159288","question":"<p>Bi\u1ebft \u0111\u1ed3 th\u1ecb hàm s\u1ed1 y = f(x) có m\u1ed9t ti\u1ec7m c\u1eadn ngang là y = 3. Khi \u0111ó \u0111\u1ed3 th\u1ecb hàm s\u1ed1 <span class=\"math-tex\">$y=-3f(x)+11$<\/span> có m\u1ed9t ti\u1ec7m c\u1eadn ngang là<\/p>","options":["<strong>A.<\/strong> y = –4","<strong>B.<\/strong> y = 3","<strong>C.<\/strong> y = 2","<strong>D.<\/strong> y = 1"],"correct":"3","level":"3","hint":"<p>S\u1eed d\u1ee5ng \u0111\u1ecbnh ngh\u0129a \u0111\u01b0\u1eddng ti\u1ec7m c\u1eadn.<\/p>","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>C.<\/strong> y = 2.<\/span><\/p><p>Theo \u0111\u1ec1 bài ta có <span class=\"math-tex\">$\\displaystyle\\lim_{x\\to\\pm\\infty}y=3$<\/span>.<\/p><p><span class=\"math-tex\">$\\displaystyle\\lim_{x\\to\\pm\\infty}y=\\displaystyle\\lim_{x\\to\\pm\\infty}(-3f(x)+11)=-3.3+11=2$<\/span>.<\/p><p>V\u1eady \u0111\u1ed3 th\u1ecb hàm s\u1ed1 <span class=\"math-tex\">$y=-3f(x)+11$<\/span> có m\u1ed9t ti\u1ec7m c\u1eadn ngang là y = 2.<br \/>.<\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2024-08-11 04:38:49","option_type":"txt","len":1}]}