{"common":{"save":0,"post_id":"7819","level":2,"total":10,"point":10,"point_extra":0},"segment":[{"id":"7583","post_id":"7819","mon_id":"1159278","chapter_id":"1159327","question":"<p>Rút g\u1ecdn bi\u1ec3u th\u1ee9c <span class=\"math-tex\">$\\dfrac{y}{x}.\\sqrt{\\dfrac{x^2}{y^4}}$<\/span> v\u1edbi x > 0, y < 0 \u0111\u01b0\u1ee3c k\u1ebft qu\u1ea3 là:<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$-\\dfrac{1}{y}$<\/span>","<strong>B.<\/strong> y","<strong>C.<\/strong> –y","<strong>D.<\/strong> <span class=\"math-tex\">$\\dfrac{1}{y}$<\/span>"],"correct":"4","level":"2","hint":"","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>D.<\/strong> <span class=\"math-tex\">$\\dfrac{1}{y}$<\/span> <\/span><\/p><p>Vì x > 0, y < 0 nên |x| = x, |y| = –y, |y²| = y². Ta có:<\/p><p><span class=\"math-tex\">$\\dfrac{y}{x}.\\sqrt{\\dfrac{x^2}{y^4}}$<\/span> <span class=\"math-tex\">$=\\dfrac{y}{x}.\\dfrac{\\sqrt{x^2}}{\\sqrt{y^4}}$<\/span> <span class=\"math-tex\">$=\\dfrac{y}{x}.\\dfrac{|x|}{|y^2|}$<\/span> <span class=\"math-tex\">$=\\dfrac{y}{x}.\\dfrac{x}{y^2}$<\/span> <span class=\"math-tex\">$=\\dfrac{1}{y}$<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"127","test":"0","date":"2024-10-11 02:28:34","option_type":"math","len":0},{"id":"7585","post_id":"7819","mon_id":"1159278","chapter_id":"1159327","question":"<p>Giá tr\u1ecb bi\u1ec3u th\u1ee9c <span class=\"math-tex\">$T=\\sqrt{3\\dfrac{1}{16}.2\\dfrac{14}{25}}$<\/span> b\u1eb1ng:<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$T=-\\dfrac{14}{5}$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$T=\\dfrac{\\sqrt{6}}{20}$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$T=\\dfrac{14}{5}$<\/span>","<strong>D.<\/strong> <span class=\"math-tex\">$T=\\dfrac{2\\sqrt{6}}{15}$<\/span>"],"correct":"3","level":"2","hint":"","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>C.<\/strong> <span class=\"math-tex\">$T=\\dfrac{14}{5}$<\/span><\/span><\/p><p><span class=\"math-tex\">$T=\\sqrt{3\\dfrac{1}{16}.2\\dfrac{14}{25}}$<\/span> <span class=\"math-tex\">$=\\sqrt{\\dfrac{49}{16}.\\dfrac{64}{25}}$<\/span> <span class=\"math-tex\">$=\\sqrt{\\dfrac{49}{16}}.\\sqrt{\\dfrac{64}{25}}$<\/span> <span class=\"math-tex\">$=\\dfrac{\\sqrt{49}}{\\sqrt{16}}.\\dfrac{\\sqrt{64}}{\\sqrt{25}}$<\/span> <span class=\"math-tex\">$=\\dfrac{7}{4}.\\dfrac{8}{5}$<\/span> <span class=\"math-tex\">$=\\dfrac{14}{5}$<\/span>.<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"127","test":"0","date":"2024-10-11 02:34:28","option_type":"math","len":0},{"id":"7587","post_id":"7819","mon_id":"1159278","chapter_id":"1159327","question":"<p>Giá tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c <span class=\"math-tex\">$(1+\\sqrt{2}+\\sqrt{3}).(1+\\sqrt{2}-\\sqrt{3})$<\/span> b\u1eb1ng:<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$\\sqrt{2}$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$2\\sqrt{2}$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$3\\sqrt{2}$<\/span>","<strong>D.<\/strong> <span class=\"math-tex\">$4\\sqrt{2}$<\/span>"],"correct":"2","level":"2","hint":"","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>B.<\/strong> <span class=\"math-tex\">$2\\sqrt{2}$<\/span><\/span><\/p><p><span class=\"math-tex\">$(1+\\sqrt{2}+\\sqrt{3}).(1+\\sqrt{2}-\\sqrt{3})$<\/span> <\/p><p><span class=\"math-tex\">$=(1+\\sqrt{2})^2-(\\sqrt{3})^2$<\/span><\/p><p><span class=\"math-tex\">$=1+2+2\\sqrt{2}-3$<\/span><\/p><p><span class=\"math-tex\">$=2\\sqrt{2}$<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"127","test":"0","date":"2024-10-11 02:38:28","option_type":"math","len":0}]}
