{"save":1,"level":1,"time":"90","total":34,"point":5,"segment":[{"id":"4065","test_id":"494","question":"<p>C\u1ea5p s\u1ed1 c\u1ed9ng&nbsp;<span class=\"math-tex\">$(u_n)$<\/span>&nbsp;c&oacute;&nbsp;<span class=\"math-tex\">$u_1=1$<\/span>&nbsp;v&agrave;&nbsp;<span class=\"math-tex\">$u_2=3$<\/span>. S\u1ed1 h\u1ea1ng&nbsp;<span class=\"math-tex\">$u_5$<\/span>&nbsp;c\u1ee7a c\u1ea5p s\u1ed1 c\u1ed9ng l&agrave;<\/p>","options":["A. 11","B. 7","C. 5","D. 9"],"correct":"4","answer":"<p>\u0110&aacute;p &aacute;n \u0111&uacute;ng l&agrave; :&nbsp;<span style=\"color:#27ae60;\"><strong>D. 9<\/strong><\/span><\/p><p>Ta c&oacute;&nbsp;<span class=\"math-tex\">$d= u_2-u_1=2$<\/span><\/p><p>V\u1eady&nbsp;<span class=\"math-tex\">$u_5=u_1+4d=1+4.2=9$<\/span>.<\/p>","type":"choose","user_id":"156","test":"1","date":"2025-05-21 16:20:32"},{"id":"4066","test_id":"494","question":"<p>T\u1ea5t c\u1ea3 c&aacute;c nghi\u1ec7m c\u1ee7a ph\u01b0\u01a1ng tr&igrave;nh&nbsp;<span class=\"math-tex\">$2cosx-1 = 0 $<\/span>&nbsp;l&agrave;&nbsp;<\/p>","options":["A.&nbsp;<span class=\"math-tex\">$x=\\pm \\frac{\\pi}{3}+k2\\pi (k\\in \\mathbb{Z})$<\/span>","B.&nbsp;<span class=\"math-tex\">$x=\\pm \\frac{\\pi}{3}+k\\pi (k\\in \\mathbb{Z})$<\/span>","C.&nbsp;<span class=\"math-tex\">$x= \\frac{\\pi}{3}+k2\\pi (k\\in \\mathbb{Z})$<\/span>","D.&nbsp;<span class=\"math-tex\">$x=- \\frac{\\pi}{3}+k2\\pi (k\\in \\mathbb{Z})$<\/span>"],"correct":"1","answer":"<p>\u0110&aacute;p &aacute;n \u0111&uacute;ng l&agrave; :<span style=\"color:#27ae60;\"><strong> A.&nbsp;<span class=\"math-tex\">$x=\\pm \\frac{\\pi}{3}+k2\\pi (k\\in \\mathbb{Z})$<\/span>&nbsp;<\/strong><\/span><\/p><p>Ta c&oacute;&nbsp;<span class=\"math-tex\">$2cosx-1 = 0 \\Leftrightarrow cosx=\\frac{1}{2}=cos(\\frac{\\pi}{3})\\Leftrightarrow x=\\pm \\frac{\\pi}{3}+k2\\pi (k\\in \\mathbb{Z})$<\/span><\/p>","type":"choose","user_id":"156","test":"1","date":"2025-05-21 16:27:36"}]}