{"common":{"save":0,"post_id":"7043","level":2,"total":10,"point":10,"point_extra":0},"segment":[{"id":"4810","post_id":"7043","mon_id":"1158924","chapter_id":"1159141","question":"<p>Kh\u1eb3ng \u0111\u1ecbnh n&agrave;o sau \u0111&acirc;y <strong>\u0111&uacute;ng<\/strong>?<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$cos^2x=\\dfrac{1+cos2x}{2}$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$cos^2x=\\dfrac{1-cos2x}{2}$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$cos^2x=\\dfrac{1-sin2x}{2}$<\/span>","<strong>D.<\/strong> <span class=\"math-tex\">$cos^2x=\\dfrac{1+sin2x}{2}$<\/span>"],"correct":"1","level":"2","hint":"","answer":"<p>Ch\u1ecdn&nbsp;<span style=\"color:#16a085;\"><strong>A.<\/strong>&nbsp;<span class=\"math-tex\">$cos^2x=\\dfrac{1+cos2x}{2}$<\/span><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2023-12-03 02:10:48","option_type":"math","len":0},{"id":"4812","post_id":"7043","mon_id":"1158924","chapter_id":"1159141","question":"<p>Bi\u1ebft&nbsp;<span class=\"math-tex\">$cos2x=\\dfrac{2}{3}$<\/span>. T&iacute;nh&nbsp;<span class=\"math-tex\">$sin\\bigg(x-\\dfrac{\\pi}{3}\\bigg).sin\\bigg(x+\\dfrac{\\pi}{3}\\bigg)$<\/span>.<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$\\dfrac{7}{12}$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$-\\dfrac{1}{12}$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$-\\dfrac{7}{12}$<\/span>","<strong>D.<\/strong> <span class=\"math-tex\">$\\dfrac{1}{12}$<\/span>"],"correct":"3","level":"2","hint":"","answer":"<p><span class=\"math-tex\">$sin\\bigg(x-\\dfrac{\\pi}{3}\\bigg).sin\\bigg(x+\\dfrac{\\pi}{3}\\bigg)$<\/span><\/p><p>=&nbsp;<span class=\"math-tex\">$\\dfrac{1}{2}\\bigg( cos\\dfrac{2\\pi}{3}-cos2x \\bigg)$<\/span><\/p><p>=&nbsp;<span class=\"math-tex\">$\\dfrac{1}{2}\\bigg( -\\dfrac{1}{2}-\\dfrac{2}{3} \\bigg)$<\/span><\/p><p>=&nbsp;<span class=\"math-tex\">$-\\dfrac{7}{12}$<\/span><\/p><p>Ch\u1ecdn&nbsp;<span style=\"color:#16a085;\"><strong>C.<\/strong>&nbsp;<span class=\"math-tex\">$-\\dfrac{7}{12}$<\/span><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2023-12-03 02:21:51","option_type":"math","len":0},{"id":"4814","post_id":"7043","mon_id":"1158924","chapter_id":"1159141","question":"<p>H&agrave;m s\u1ed1 n&agrave;o l&agrave; h&agrave;m s\u1ed1 ch\u1eb5n?<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$y=sin2x$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$y=tan2x$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$y=sinx+cosx$<\/span>","<strong>D.<\/strong> <span class=\"math-tex\">$y=cos3x$<\/span>"],"correct":"4","level":"2","hint":"","answer":"<p>H&agrave;m s\u1ed1&nbsp;<span class=\"math-tex\">$y=cos3x$<\/span>&nbsp;l&agrave; h&agrave;m s\u1ed1 ch\u1eb5n.<\/p><p>Ch\u1ecdn&nbsp;<span style=\"color:#16a085;\"><strong>D.<\/strong>&nbsp;<span class=\"math-tex\">$y=cos3x$<\/span><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2023-12-03 02:24:12","option_type":"math","len":0}]}