[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.39,0:00:03.49,Default,,0000,0000,0000,,Trong video trước, chúng ta
Dialogue: 0,0:00:03.49,0:00:10.01,Default,,0000,0000,0000,,đã tìm hiểu về
Dialogue: 0,0:00:10.01,0:00:13.19,Default,,0000,0000,0000,,arcsin của x
Dialogue: 0,0:00:13.19,0:00:16.36,Default,,0000,0000,0000,,Và chúng ta biết
Dialogue: 0,0:00:16.36,0:00:20.10,Default,,0000,0000,0000,,ký hiệu này có nghĩa là
Dialogue: 0,0:00:20.10,0:00:22.47,Default,,0000,0000,0000,,sin của một góc nào đó bằng x.
Dialogue: 0,0:00:22.47,0:00:25.52,Default,,0000,0000,0000,,Và trong những ví dụ trước chúng ta đã \Ngiải một số phương trình.
Dialogue: 0,0:00:25.52,0:00:28.23,Default,,0000,0000,0000,,Vậy cũng như vậy,
Dialogue: 0,0:00:28.23,0:00:31.81,Default,,0000,0000,0000,,trước hết chúng ta có thể viết lại biểu thức thành
Dialogue: 0,0:00:31.81,0:00:33.54,Default,,0000,0000,0000,,hàm ngược của sin x là bằng gì.
Dialogue: 0,0:00:33.54,0:00:35.14,Default,,0000,0000,0000,,Chúng ta có những phát biểu giống nhau,
Dialogue: 0,0:00:35.14,0:00:37.48,Default,,0000,0000,0000,,có hai cách để viết hàm ngược của sin.
Dialogue: 0,0:00:37.48,0:00:39.79,Default,,0000,0000,0000,,Đây là arcsin của x
Dialogue: 0,0:00:39.79,0:00:41.46,Default,,0000,0000,0000,,chứ không phải là arcsin x mũ âm 1
Dialogue: 0,0:00:41.46,0:00:45.34,Default,,0000,0000,0000,,Chúng ta đơn giản chí nói rằng sin của
Dialogue: 0,0:00:45.34,0:00:46.92,Default,,0000,0000,0000,,góc nào là bằng x,
Dialogue: 0,0:00:46.92,0:00:48.47,Default,,0000,0000,0000,,như chúng ta đã làm trong video trước.
Dialogue: 0,0:00:48.47,0:00:52.02,Default,,0000,0000,0000,,Vậy, cúng giống như vậy,
Dialogue: 0,0:00:52.02,0:00:58.77,Default,,0000,0000,0000,,Khi chúng ta được hỏi hàm ngược của
Dialogue: 0,0:00:58.77,0:01:02.01,Default,,0000,0000,0000,,tan x là gì,
Dialogue: 0,0:01:02.01,0:01:05.14,Default,,0000,0000,0000,,thì chúng ta nên lập tức nhận ra rằng
Dialogue: 0,0:01:05.14,0:01:09.08,Default,,0000,0000,0000,,phát biểu đó đơn giản có nghĩa là
Dialogue: 0,0:01:09.08,0:01:10.44,Default,,0000,0000,0000,,tan của một góc nào đó là bằng x,
Dialogue: 0,0:01:10.44,0:01:13.38,Default,,0000,0000,0000,,và chúng ta chỉ cần tính giá trị của góc đó.
Dialogue: 0,0:01:13.38,0:01:14.84,Default,,0000,0000,0000,,Bây giờ chúng ta sẽ làm một ví dụ
Dialogue: 0,0:01:14.84,0:01:17.06,Default,,0000,0000,0000,,Giả dụ như
Dialogue: 0,0:01:17.06,0:01:20.15,Default,,0000,0000,0000,,thầy hỏi
Dialogue: 0,0:01:20.15,0:01:23.79,Default,,0000,0000,0000,,thầy hỏi chúng ta rằng,
Dialogue: 0,0:01:23.79,0:01:27.97,Default,,0000,0000,0000,,arctan của âm 1 là gì?
Dialogue: 0,0:01:27.97,0:01:30.19,Default,,0000,0000,0000,,Thì câu hỏi đấy cũng có nghĩa là
Dialogue: 0,0:01:30.19,0:01:32.51,Default,,0000,0000,0000,,hàm ngược của tan x của 1 là gì.
Dialogue: 0,0:01:32.51,0:01:35.19,Default,,0000,0000,0000,,2 câu hỏi này giống y hệt nhau.
Dialogue: 0,0:01:35.19,0:01:37.43,Default,,0000,0000,0000,,Và điều bạn nên làm là - nếu bạn không
Dialogue: 0,0:01:37.43,0:01:40.20,Default,,0000,0000,0000,,nhớ được thì bạn có thể vẽ\Nmột đường tròn đơn vị -
Dialogue: 0,0:01:40.20,0:01:42.64,Default,,0000,0000,0000,,Trước khi giải bài toán này thì \Ntôi sẽ đi qua
Dialogue: 0,0:01:42.64,0:01:44.33,Default,,0000,0000,0000,,định nghĩa chính xác của hàm tan.
Dialogue: 0,0:01:44.33,0:01:48.89,Default,,0000,0000,0000,,tan của theta chỉ là một hàm lượng giác\Nđược định nghĩa bởi
Dialogue: 0,0:01:48.89,0:01:52.63,Default,,0000,0000,0000,,thương của hai hàm lượng giác, là
Dialogue: 0,0:01:52.63,0:01:56.69,Default,,0000,0000,0000,,sin theta chia cho cosin theta.
Dialogue: 0,0:01:56.69,0:02:00.67,Default,,0000,0000,0000,,Và sin theta là giá trị\Ntung độ của một điểm
Dialogue: 0,0:02:00.67,0:02:03.01,Default,,0000,0000,0000,,nằm trên đường tròn đơn vị.
Dialogue: 0,0:02:03.01,0:02:06.73,Default,,0000,0000,0000,,Tương tự, cosin theta là giá trị\Nhoành độ của một điểm nằm trên
Dialogue: 0,0:02:06.73,0:02:08.60,Default,,0000,0000,0000,,đường tròn đơn vị. Nếu tôi vẽ
Dialogue: 0,0:02:08.60,0:02:11.11,Default,,0000,0000,0000,,một đường tròn đơn vị tại đây.
Dialogue: 0,0:02:11.11,0:02:14.77,Default,,0000,0000,0000,,Nếu tôi có một đường tròn đơn vị \Nnhư thế này,
Dialogue: 0,0:02:14.77,0:02:17.98,Default,,0000,0000,0000,,và có một góc theta
Dialogue: 0,0:02:17.98,0:02:20.94,Default,,0000,0000,0000,,ở đây.
Dialogue: 0,0:02:20.94,0:02:25.64,Default,,0000,0000,0000,,Và đây là tọa độ (x, y) của tôi.
Dialogue: 0,0:02:25.64,0:02:29.38,Default,,0000,0000,0000,,Chúng ta đã biết rằng giá trị tung độ
Dialogue: 0,0:02:29.38,0:02:30.88,Default,,0000,0000,0000,,của tọa độ là sin theta.
Dialogue: 0,0:02:30.88,0:02:32.78,Default,,0000,0000,0000,,Để tôi kéo sang đây.
Dialogue: 0,0:02:32.78,0:02:34.21,Default,,0000,0000,0000,,sin theta.
Dialogue: 0,0:02:34.21,0:02:38.73,Default,,0000,0000,0000,,Và giá trị hoành độ là cos theta.
Dialogue: 0,0:02:38.73,0:02:40.20,Default,,0000,0000,0000,,Vậy tan của góc này bằng bao nhiêu?
Dialogue: 0,0:02:40.20,0:02:46.67,Default,,0000,0000,0000,,Nó sẽ bằng khoảng này \Nchia cho khoảng này
Dialogue: 0,0:02:46.67,0:02:49.97,Default,,0000,0000,0000,,
Dialogue: 0,0:02:49.97,0:02:52.52,Default,,0000,0000,0000,,
Dialogue: 0,0:02:52.52,0:02:56.25,Default,,0000,0000,0000,,
Dialogue: 0,0:02:56.25,0:02:58.70,Default,,0000,0000,0000,,
Dialogue: 0,0:02:58.70,0:03:01.95,Default,,0000,0000,0000,,
Dialogue: 0,0:03:01.95,0:03:04.57,Default,,0000,0000,0000,,
Dialogue: 0,0:03:04.57,0:03:05.73,Default,,0000,0000,0000,,
Dialogue: 0,0:03:05.73,0:03:11.66,Default,,0000,0000,0000,,
Dialogue: 0,0:03:11.66,0:03:14.35,Default,,0000,0000,0000,,
Dialogue: 0,0:03:14.35,0:03:19.55,Default,,0000,0000,0000,,
Dialogue: 0,0:03:19.55,0:03:22.60,Default,,0000,0000,0000,,
Dialogue: 0,0:03:22.60,0:03:23.88,Default,,0000,0000,0000,,
Dialogue: 0,0:03:23.88,0:03:26.44,Default,,0000,0000,0000,,
Dialogue: 0,0:03:26.44,0:03:29.83,Default,,0000,0000,0000,,
Dialogue: 0,0:03:29.83,0:03:31.32,Default,,0000,0000,0000,,
Dialogue: 0,0:03:31.32,0:03:34.83,Default,,0000,0000,0000,,
Dialogue: 0,0:03:34.83,0:03:37.96,Default,,0000,0000,0000,,
Dialogue: 0,0:03:37.96,0:03:42.88,Default,,0000,0000,0000,,
Dialogue: 0,0:03:42.88,0:03:44.44,Default,,0000,0000,0000,,
Dialogue: 0,0:03:44.44,0:03:46.45,Default,,0000,0000,0000,,
Dialogue: 0,0:03:49.100,0:03:52.43,Default,,0000,0000,0000,,
Dialogue: 0,0:03:52.43,0:03:55.58,Default,,0000,0000,0000,,
Dialogue: 0,0:03:55.58,0:03:58.71,Default,,0000,0000,0000,,
Dialogue: 0,0:03:58.71,0:04:00.58,Default,,0000,0000,0000,,
Dialogue: 0,0:04:00.58,0:04:03.94,Default,,0000,0000,0000,,
Dialogue: 0,0:04:03.94,0:04:06.41,Default,,0000,0000,0000,,
Dialogue: 0,0:04:06.41,0:04:09.25,Default,,0000,0000,0000,,
Dialogue: 0,0:04:09.25,0:04:10.63,Default,,0000,0000,0000,,
Dialogue: 0,0:04:10.63,0:04:12.88,Default,,0000,0000,0000,,
Dialogue: 0,0:04:12.88,0:04:15.12,Default,,0000,0000,0000,,
Dialogue: 0,0:04:15.12,0:04:18.68,Default,,0000,0000,0000,,
Dialogue: 0,0:04:18.68,0:04:20.25,Default,,0000,0000,0000,,
Dialogue: 0,0:04:20.25,0:04:22.44,Default,,0000,0000,0000,,
Dialogue: 0,0:04:22.44,0:04:23.81,Default,,0000,0000,0000,,
Dialogue: 0,0:04:23.81,0:04:28.04,Default,,0000,0000,0000,,
Dialogue: 0,0:04:28.04,0:04:31.61,Default,,0000,0000,0000,,
Dialogue: 0,0:04:31.61,0:04:33.38,Default,,0000,0000,0000,,
Dialogue: 0,0:04:33.38,0:04:36.21,Default,,0000,0000,0000,,
Dialogue: 0,0:04:36.21,0:04:39.50,Default,,0000,0000,0000,,
Dialogue: 0,0:04:39.50,0:04:40.96,Default,,0000,0000,0000,,
Dialogue: 0,0:04:40.96,0:04:43.43,Default,,0000,0000,0000,,
Dialogue: 0,0:04:43.43,0:04:46.17,Default,,0000,0000,0000,,
Dialogue: 0,0:04:46.17,0:04:47.81,Default,,0000,0000,0000,,
Dialogue: 0,0:04:47.81,0:04:50.69,Default,,0000,0000,0000,,
Dialogue: 0,0:04:50.69,0:04:54.70,Default,,0000,0000,0000,,
Dialogue: 0,0:04:54.70,0:04:57.67,Default,,0000,0000,0000,,
Dialogue: 0,0:04:57.67,0:04:59.36,Default,,0000,0000,0000,,
Dialogue: 0,0:04:59.36,0:05:04.06,Default,,0000,0000,0000,,
Dialogue: 0,0:05:04.06,0:05:05.98,Default,,0000,0000,0000,,
Dialogue: 0,0:05:09.22,0:05:13.71,Default,,0000,0000,0000,,
Dialogue: 0,0:05:13.71,0:05:15.25,Default,,0000,0000,0000,,
Dialogue: 0,0:05:15.25,0:05:16.91,Default,,0000,0000,0000,,
Dialogue: 0,0:05:16.91,0:05:25.16,Default,,0000,0000,0000,,
Dialogue: 0,0:05:25.16,0:05:28.17,Default,,0000,0000,0000,,
Dialogue: 0,0:05:28.17,0:05:31.20,Default,,0000,0000,0000,,
Dialogue: 0,0:05:31.20,0:05:36.67,Default,,0000,0000,0000,,
Dialogue: 0,0:05:36.67,0:05:39.11,Default,,0000,0000,0000,,
Dialogue: 0,0:05:39.11,0:05:40.92,Default,,0000,0000,0000,,
Dialogue: 0,0:05:40.92,0:05:42.35,Default,,0000,0000,0000,,
Dialogue: 0,0:05:42.35,0:05:47.53,Default,,0000,0000,0000,,
Dialogue: 0,0:05:47.53,0:05:49.88,Default,,0000,0000,0000,,
Dialogue: 0,0:05:49.88,0:05:51.89,Default,,0000,0000,0000,,
Dialogue: 0,0:05:51.89,0:05:53.96,Default,,0000,0000,0000,,
Dialogue: 0,0:05:53.96,0:05:55.16,Default,,0000,0000,0000,,
Dialogue: 0,0:05:55.16,0:05:57.57,Default,,0000,0000,0000,,
Dialogue: 0,0:05:57.57,0:06:01.71,Default,,0000,0000,0000,,
Dialogue: 0,0:06:01.71,0:06:06.45,Default,,0000,0000,0000,,
Dialogue: 0,0:06:06.45,0:06:13.85,Default,,0000,0000,0000,,
Dialogue: 0,0:06:13.85,0:06:15.35,Default,,0000,0000,0000,,
Dialogue: 0,0:06:15.35,0:06:17.93,Default,,0000,0000,0000,,
Dialogue: 0,0:06:17.93,0:06:18.54,Default,,0000,0000,0000,,
Dialogue: 0,0:06:18.54,0:06:22.36,Default,,0000,0000,0000,,
Dialogue: 0,0:06:22.36,0:06:23.32,Default,,0000,0000,0000,,
Dialogue: 0,0:06:23.32,0:06:25.12,Default,,0000,0000,0000,,
Dialogue: 0,0:06:25.12,0:06:26.88,Default,,0000,0000,0000,,
Dialogue: 0,0:06:26.88,0:06:30.89,Default,,0000,0000,0000,,
Dialogue: 0,0:06:30.89,0:06:33.09,Default,,0000,0000,0000,,
Dialogue: 0,0:06:33.09,0:06:34.64,Default,,0000,0000,0000,,
Dialogue: 0,0:06:34.64,0:06:39.17,Default,,0000,0000,0000,,
Dialogue: 0,0:06:39.17,0:06:42.10,Default,,0000,0000,0000,,
Dialogue: 0,0:06:42.10,0:06:44.42,Default,,0000,0000,0000,,
Dialogue: 0,0:06:44.42,0:06:45.79,Default,,0000,0000,0000,,
Dialogue: 0,0:06:45.79,0:06:49.46,Default,,0000,0000,0000,,
Dialogue: 0,0:06:49.46,0:06:51.96,Default,,0000,0000,0000,,
Dialogue: 0,0:06:51.96,0:06:58.19,Default,,0000,0000,0000,,
Dialogue: 0,0:06:58.19,0:06:59.83,Default,,0000,0000,0000,,
Dialogue: 0,0:06:59.83,0:07:03.28,Default,,0000,0000,0000,,
Dialogue: 0,0:07:03.28,0:07:09.27,Default,,0000,0000,0000,,
Dialogue: 0,0:07:09.27,0:07:09.73,Default,,0000,0000,0000,,
Dialogue: 0,0:07:09.73,0:07:14.31,Default,,0000,0000,0000,,
Dialogue: 0,0:07:14.31,0:07:16.20,Default,,0000,0000,0000,,
Dialogue: 0,0:07:16.20,0:07:18.55,Default,,0000,0000,0000,,
Dialogue: 0,0:07:18.55,0:07:20.74,Default,,0000,0000,0000,,
Dialogue: 0,0:07:20.74,0:07:22.27,Default,,0000,0000,0000,,
Dialogue: 0,0:07:22.27,0:07:25.57,Default,,0000,0000,0000,,
Dialogue: 0,0:07:25.57,0:07:29.10,Default,,0000,0000,0000,,
Dialogue: 0,0:07:29.10,0:07:32.51,Default,,0000,0000,0000,,
Dialogue: 0,0:07:32.51,0:07:36.01,Default,,0000,0000,0000,,
Dialogue: 0,0:07:36.01,0:07:37.47,Default,,0000,0000,0000,,
Dialogue: 0,0:07:37.47,0:07:39.95,Default,,0000,0000,0000,,
Dialogue: 0,0:07:39.95,0:07:44.81,Default,,0000,0000,0000,,
Dialogue: 0,0:07:44.81,0:07:46.35,Default,,0000,0000,0000,,
Dialogue: 0,0:07:46.35,0:07:48.11,Default,,0000,0000,0000,,
Dialogue: 0,0:07:48.11,0:07:50.26,Default,,0000,0000,0000,,
Dialogue: 0,0:07:50.26,0:07:52.89,Default,,0000,0000,0000,,
Dialogue: 0,0:07:52.89,0:07:55.56,Default,,0000,0000,0000,,
Dialogue: 0,0:07:55.56,0:07:59.73,Default,,0000,0000,0000,,
Dialogue: 0,0:07:59.73,0:08:03.43,Default,,0000,0000,0000,,
Dialogue: 0,0:08:03.43,0:08:06.33,Default,,0000,0000,0000,,
Dialogue: 0,0:08:06.33,0:08:11.80,Default,,0000,0000,0000,,
Dialogue: 0,0:08:11.80,0:08:13.81,Default,,0000,0000,0000,,
Dialogue: 0,0:08:13.81,0:08:16.90,Default,,0000,0000,0000,,
Dialogue: 0,0:08:16.90,0:08:18.81,Default,,0000,0000,0000,,
Dialogue: 0,0:08:18.81,0:08:22.70,Default,,0000,0000,0000,,
Dialogue: 0,0:08:22.70,0:08:24.87,Default,,0000,0000,0000,,
Dialogue: 0,0:08:24.87,0:08:27.25,Default,,0000,0000,0000,,
Dialogue: 0,0:08:27.25,0:08:29.05,Default,,0000,0000,0000,,
Dialogue: 0,0:08:29.05,0:08:29.95,Default,,0000,0000,0000,,
Dialogue: 0,0:08:29.95,0:08:33.91,Default,,0000,0000,0000,,
Dialogue: 0,0:08:33.91,0:08:35.26,Default,,0000,0000,0000,,
Dialogue: 0,0:08:35.26,0:08:37.68,Default,,0000,0000,0000,,
Dialogue: 0,0:08:37.68,0:08:39.79,Default,,0000,0000,0000,,
Dialogue: 0,0:08:39.79,0:08:41.91,Default,,0000,0000,0000,,
Dialogue: 0,0:08:41.91,0:08:43.31,Default,,0000,0000,0000,,
Dialogue: 0,0:08:43.31,0:08:44.47,Default,,0000,0000,0000,,
Dialogue: 0,0:08:44.47,0:08:50.94,Default,,0000,0000,0000,,
Dialogue: 0,0:08:50.94,0:08:53.41,Default,,0000,0000,0000,,
Dialogue: 0,0:08:53.41,0:08:55.58,Default,,0000,0000,0000,,
Dialogue: 0,0:08:55.58,0:08:56.61,Default,,0000,0000,0000,,
Dialogue: 0,0:08:56.61,0:08:58.87,Default,,0000,0000,0000,,
Dialogue: 0,0:08:58.87,0:09:04.18,Default,,0000,0000,0000,,
Dialogue: 0,0:09:04.18,0:09:10.16,Default,,0000,0000,0000,,
Dialogue: 0,0:09:10.16,0:09:13.71,Default,,0000,0000,0000,,
Dialogue: 0,0:09:13.71,0:09:16.19,Default,,0000,0000,0000,,
Dialogue: 0,0:09:16.19,0:09:17.72,Default,,0000,0000,0000,,
Dialogue: 0,0:09:17.72,0:09:21.67,Default,,0000,0000,0000,,
Dialogue: 0,0:09:21.67,0:09:24.36,Default,,0000,0000,0000,,
Dialogue: 0,0:09:24.36,0:09:25.32,Default,,0000,0000,0000,,
Dialogue: 0,0:09:25.32,0:09:27.32,Default,,0000,0000,0000,,
Dialogue: 0,0:09:27.32,0:09:29.44,Default,,0000,0000,0000,,
Dialogue: 0,0:09:29.44,0:09:34.68,Default,,0000,0000,0000,,
Dialogue: 0,0:09:34.68,0:09:38.27,Default,,0000,0000,0000,,
Dialogue: 0,0:09:38.27,0:09:39.70,Default,,0000,0000,0000,,
Dialogue: 0,0:09:39.70,0:09:42.43,Default,,0000,0000,0000,,
Dialogue: 0,0:09:42.43,0:09:50.34,Default,,0000,0000,0000,,
Dialogue: 0,0:09:50.34,0:09:53.46,Default,,0000,0000,0000,,
Dialogue: 0,0:09:53.46,0:09:57.76,Default,,0000,0000,0000,,
Dialogue: 0,0:09:57.76,0:09:59.10,Default,,0000,0000,0000,,
Dialogue: 0,0:09:59.10,0:10:02.28,Default,,0000,0000,0000,,
Dialogue: 0,0:10:02.28,0:10:06.16,Default,,0000,0000,0000,,