{"common":{"save":0,"post_id":"6486","level":1,"total":10,"point":10,"point_extra":0},"segment":[{"id":"7057","mon_id":"1158767","chapter_id":"1158892","post_id":"6486","question":"<p>Ph\u01b0\u01a1ng trình nào sau \u0111ây là ph\u01b0\u01a1ng trình c\u1ee7a m\u1ed9t \u0111\u01b0\u1eddng tròn?<\/p>","options":["<strong>A. <span class=\"math-tex\">$x^2+y^2-4\\sqrt{xy}+x+8y-13=0$<\/span><\/strong>","<strong>B. <span class=\"math-tex\">$x^2+6y^2-x+5y-21=0$<\/span><\/strong>","<strong>C. <span class=\"math-tex\">$x^2+y^2-14x+2y+2018=0$<\/span><\/strong>","<strong>D. <span class=\"math-tex\">$x^2+y^2-4x-y-2=0$<\/span><\/strong>"],"correct":"4","level":"1","hint":"","answer":"<p>Ph\u01b0\u01a1ng án A: có <span class=\"math-tex\">$\\sqrt{xy}$<\/span> nên không ph\u1ea3i là ph\u01b0\u01a1ng trình \u0111\u01b0\u1eddng tròn.<\/p><p>Ph\u01b0\u01a1ng án B: có các h\u1ec7 s\u1ed1 b\u1eadc hai không b\u1eb1ng nhau nên không ph\u1ea3i là ph\u01b0\u01a1ng trình \u0111\u01b0\u1eddng tròn.<br \/>Ph\u01b0\u01a1ng án C: ta có <strong><span class=\"math-tex\">$x^2+y^2-14x+2y+2018=0$<\/span> <span class=\"math-tex\">$\\Leftrightarrow(x-7)^2+(y+1)^2+1968=0$<\/span><\/strong> không t\u1ed3n t\u1ea1i x, y nên c\u0169ng không ph\u1ea3i ph\u01b0\u01a1ng trình \u0111\u01b0\u1eddng tròn.<\/p><p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>D. <span class=\"math-tex\">$x^2+y^2-4x-y-2=0$<\/span><\/strong><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2023-06-01 05:07:09","option_type":"math","len":0},{"id":"7059","mon_id":"1158767","chapter_id":"1158892","post_id":"6486","question":"<p>Tìm t\u1ea5t c\u1ea3 các giá tr\u1ecb c\u1ee7a tham s\u1ed1 m \u0111\u1ec3 ph\u01b0\u01a1ng trình <span class=\"math-tex\">$x^2+y^2-2(m+1)x+2my-3m-2=0$<\/span> là ph\u01b0\u01a1ng trình \u0111\u01b0\u1eddng tròn.<\/p>","options":["<strong>A. <span class=\"math-tex\">$-3< m <1$<\/span><\/strong>","<strong>B. <span class=\"math-tex\">$m<-3$<\/span><\/strong> ho\u1eb7c <span class=\"math-tex\">$m>-1$<\/span>","<strong>C. <span class=\"math-tex\">$m<\\dfrac{-3}{2}$<\/span><\/strong> ho\u1eb7c <span class=\"math-tex\">$m>1$<\/span>","<strong>D. <span class=\"math-tex\">$m<\\dfrac{-3}{2}$<\/span><\/strong> ho\u1eb7c <span class=\"math-tex\">$m>-1$<\/span>"],"correct":"4","level":"1","hint":"","answer":"<p>V\u1edbi <span class=\"math-tex\">$x^2+y^2-2(m+1)x+2my-3m-2=0$<\/span> thì <span class=\"math-tex\">$a=m+1;b=-m;c=-3m-2$<\/span>.<\/p><p>Ph\u01b0\u01a1ng trình trên là ph\u01b0\u01a1ng trình \u0111\u01b0\u1eddng tròn <span class=\"math-tex\">$\\Leftrightarrow a^2+b^2-c>0$<\/span><\/p><p><span class=\"math-tex\">$\\Leftrightarrow 2m^2+5m+3>0$<\/span> <span class=\"math-tex\">$\\Leftrightarrow $<\/span> <strong><span class=\"math-tex\">$m<\\dfrac{-3}{2}$<\/span><\/strong> ho\u1eb7c <span class=\"math-tex\">$m>-1$<\/span>.<\/p><p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>D. <span class=\"math-tex\">$m<\\dfrac{-3}{2}$<\/span><\/strong> ho\u1eb7c <span class=\"math-tex\">$m>-1$<\/span><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2023-06-01 08:13:24","option_type":"math","len":0},{"id":"7060","mon_id":"1158767","chapter_id":"1158892","post_id":"6486","question":"<p>Tìm t\u1ea5t c\u1ea3 các giá tr\u1ecb c\u1ee7a tham s\u1ed1 m \u0111\u1ec3 ph\u01b0\u01a1ng trình <span class=\"math-tex\">$x^2+y^2-2mx-2(m-2)y+2m=0\\space(1)$<\/span> là ph\u01b0\u01a1ng trình \u0111\u01b0\u1eddng tròn.<\/p>","options":["<strong>A. <\/strong><span class=\"math-tex\">$m=2$<\/span>","<strong>B. <span class=\"math-tex\">$m<1$<\/span><\/strong> ho\u1eb7c <span class=\"math-tex\">$m>2$<\/span>","<strong>C. <\/strong><span class=\"math-tex\">$1< m< 2$<\/span>","<strong>D. <span class=\"math-tex\">$m=1$<\/span><\/strong> ho\u1eb7c <span class=\"math-tex\">$m=2$<\/span>"],"correct":"2","level":"1","hint":"","answer":"<p>V\u1edbi <span class=\"math-tex\">$x^2+y^2-2mx-2(m-2)y+2m=0\\space(1)$<\/span> thì <span class=\"math-tex\">$a=m;b=m-2;c=2m$<\/span>.<\/p><p>Ph\u01b0\u01a1ng trình (1) là ph\u01b0\u01a1ng trình \u0111\u01b0\u1eddng tròn <span class=\"math-tex\">$\\Leftrightarrow a^2+b^2-c>0$<\/span><\/p><p><span class=\"math-tex\">$\\Leftrightarrow m^2-3m+2>0$<\/span> <span class=\"math-tex\">$\\Leftrightarrow $<\/span> <strong><span class=\"math-tex\">$m<1$<\/span><\/strong> ho\u1eb7c <span class=\"math-tex\">$m>2$<\/span>.<\/p><p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>B. <span class=\"math-tex\">$m<1$<\/span><\/strong> ho\u1eb7c <span class=\"math-tex\">$m>2$<\/span><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2023-06-01 08:20:16","option_type":"math","len":0}]}