[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.82,0:00:02.34,Default,,0000,0000,0000,,기본 연산을 할 때
Dialogue: 0,0:00:02.34,0:00:04.59,Default,,0000,0000,0000,,구체적인 숫자들을 볼 수 있어요
Dialogue: 0,0:00:04.59,0:00:07.51,Default,,0000,0000,0000,,23 + 5를 살펴봅시다
Dialogue: 0,0:00:07.51,0:00:09.06,Default,,0000,0000,0000,,이 숫자들을 보고
Dialogue: 0,0:00:09.06,0:00:10.94,Default,,0000,0000,0000,,계산을 할 수 있어요
Dialogue: 0,0:00:10.94,0:00:11.66,Default,,0000,0000,0000,,28이에요
Dialogue: 0,0:00:11.66,0:00:13.90,Default,,0000,0000,0000,,2 x 7도 있고
Dialogue: 0,0:00:13.90,0:00:17.48,Default,,0000,0000,0000,,3 ÷ 4도 있어요
Dialogue: 0,0:00:17.48,0:00:18.45,Default,,0000,0000,0000,,모든 경우에서
Dialogue: 0,0:00:18.45,0:00:20.87,Default,,0000,0000,0000,,무슨 숫자를 다루는지 알고 있어요
Dialogue: 0,0:00:20.87,0:00:25.51,Default,,0000,0000,0000,,대수의 세계로 들어가면서
Dialogue: 0,0:00:25.51,0:00:25.87,Default,,0000,0000,0000,,
Dialogue: 0,0:00:25.87,0:00:29.52,Default,,0000,0000,0000,,변수라는 개념을 다루게 되요
Dialogue: 0,0:00:29.52,0:00:32.93,Default,,0000,0000,0000,,변수에 대해서는 여러 가지 방식으로\N생각해 볼 수 있어요
Dialogue: 0,0:00:32.93,0:00:33.21,Default,,0000,0000,0000,,
Dialogue: 0,0:00:33.21,0:00:35.99,Default,,0000,0000,0000,,변수는 단지 바뀔 수 있는 값이나 식이에요
Dialogue: 0,0:00:35.99,0:00:36.25,Default,,0000,0000,0000,,
Dialogue: 0,0:00:36.25,0:00:39.46,Default,,0000,0000,0000,,이 식들이 가지는 값은 변할 수 있죠
Dialogue: 0,0:00:39.46,0:00:41.79,Default,,0000,0000,0000,,예를 들면
Dialogue: 0,0:00:41.79,0:00:44.78,Default,,0000,0000,0000,,{\b1}x + 5 {\b0}라고 쓴다면
Dialogue: 0,0:00:44.78,0:00:46.65,Default,,0000,0000,0000,,이것은 하나의 식이에요
Dialogue: 0,0:00:46.65,0:00:48.72,Default,,0000,0000,0000,,이것이 나타내는 값은
Dialogue: 0,0:00:48.72,0:00:51.86,Default,,0000,0000,0000,,x가 무엇이냐에 따라 달라지죠
Dialogue: 0,0:00:51.86,0:00:56.66,Default,,0000,0000,0000,,만약 x가 1이면
Dialogue: 0,0:00:56.66,0:01:01.72,Default,,0000,0000,0000,,x + 5 라는 식은
Dialogue: 0,0:01:01.72,0:01:06.82,Default,,0000,0000,0000,,이 때 x는 1이기 때문에
Dialogue: 0,0:01:06.82,0:01:07.07,Default,,0000,0000,0000,,
Dialogue: 0,0:01:07.07,0:01:08.32,Default,,0000,0000,0000,,1 + 5가 되고
Dialogue: 0,0:01:08.32,0:01:11.10,Default,,0000,0000,0000,,x + 5는 6 이되요
Dialogue: 0,0:01:11.10,0:01:16.82,Default,,0000,0000,0000,,만약 x가 -7 이면
Dialogue: 0,0:01:16.82,0:01:22.18,Default,,0000,0000,0000,,x + 5는
Dialogue: 0,0:01:22.18,0:01:24.12,Default,,0000,0000,0000,,x 가 -7이기 때문에
Dialogue: 0,0:01:24.12,0:01:29.11,Default,,0000,0000,0000,,-7 + 5가 되어 -2가 되겠죠
Dialogue: 0,0:01:29.11,0:01:29.44,Default,,0000,0000,0000,,
Dialogue: 0,0:01:29.44,0:01:34.02,Default,,0000,0000,0000,,여기 있는 x는 변수이고
Dialogue: 0,0:01:34.02,0:01:39.46,Default,,0000,0000,0000,,이 식은 주어진 값에 따라 달라지죠
Dialogue: 0,0:01:39.46,0:01:39.95,Default,,0000,0000,0000,,
Dialogue: 0,0:01:39.95,0:01:42.17,Default,,0000,0000,0000,,방정식에서도 볼 수 있어요
Dialogue: 0,0:01:42.17,0:01:45.42,Default,,0000,0000,0000,,식과 방정식의 차이를 아는 것은
Dialogue: 0,0:01:45.42,0:01:46.90,Default,,0000,0000,0000,,매우 중요해요
Dialogue: 0,0:01:46.90,0:01:50.45,Default,,0000,0000,0000,,식은 단지 어떤 값을 나타내는
Dialogue: 0,0:01:50.45,0:01:54.04,Default,,0000,0000,0000,,어떤 양을 나타내는 표현이에요
Dialogue: 0,0:01:54.04,0:01:54.33,Default,,0000,0000,0000,,
Dialogue: 0,0:01:54.33,0:01:56.64,Default,,0000,0000,0000,,식은 예를 들면
Dialogue: 0,0:01:56.64,0:01:57.98,Default,,0000,0000,0000,,아까 여기서 봤던
Dialogue: 0,0:01:57.98,0:01:59.26,Default,,0000,0000,0000,,x + 5와 같은 거에요
Dialogue: 0,0:01:59.26,0:02:05.48,Default,,0000,0000,0000,,이 식의 값은 변수의 값에 따라서 바뀔 거에요
Dialogue: 0,0:02:05.48,0:02:05.74,Default,,0000,0000,0000,,
Dialogue: 0,0:02:05.74,0:02:09.06,Default,,0000,0000,0000,,x가 다른 값이 되면 달라지는 거죠
Dialogue: 0,0:02:09.06,0:02:11.57,Default,,0000,0000,0000,,식의 다른 예를 들면
Dialogue: 0,0:02:11.57,0:02:13.15,Default,,0000,0000,0000,,y + z가 있어요
Dialogue: 0,0:02:13.15,0:02:14.34,Default,,0000,0000,0000,,전부 변수에요
Dialogue: 0,0:02:14.34,0:02:16.99,Default,,0000,0000,0000,,y가 1이고 z가 2이면
Dialogue: 0,0:02:16.99,0:02:18.56,Default,,0000,0000,0000,,1 + 2가 되겠죠
Dialogue: 0,0:02:18.56,0:02:21.39,Default,,0000,0000,0000,,y가 0이고 z가 -1이면
Dialogue: 0,0:02:21.39,0:02:24.07,Default,,0000,0000,0000,,0 + (-1)이 될 거에요
Dialogue: 0,0:02:24.07,0:02:25.90,Default,,0000,0000,0000,,이것들은
Dialogue: 0,0:02:25.90,0:02:31.78,Default,,0000,0000,0000,,식 안에 있는 변수들 각각의 값에 따라\N답이 달라져요
Dialogue: 0,0:02:31.78,0:02:32.03,Default,,0000,0000,0000,,\N
Dialogue: 0,0:02:32.03,0:02:32.33,Default,,0000,0000,0000,,
Dialogue: 0,0:02:32.33,0:02:35.42,Default,,0000,0000,0000,,방정식의 경우에는 식이 서로 같다고\N가정하고 시작해요
Dialogue: 0,0:02:35.42,0:02:35.68,Default,,0000,0000,0000,,
Dialogue: 0,0:02:35.68,0:02:38.57,Default,,0000,0000,0000,,그래서 {\b1}equations{\b0}라고 하는 거에요
Dialogue: 0,0:02:38.57,0:02:40.12,Default,,0000,0000,0000,,두 개를 같다고 보는 거죠
Dialogue: 0,0:02:40.12,0:02:42.92,Default,,0000,0000,0000,,방정식에서는 한 식이
Dialogue: 0,0:02:42.92,0:02:45.78,Default,,0000,0000,0000,,다른 식과 같다는 걸 볼 수 있어요
Dialogue: 0,0:02:45.78,0:02:47.87,Default,,0000,0000,0000,,예를 들면
Dialogue: 0,0:02:47.87,0:02:52.06,Default,,0000,0000,0000,,x + 3 = 1
Dialogue: 0,0:02:52.06,0:02:57.61,Default,,0000,0000,0000,,이렇게 한 개의 값을 모르는 방정식에서는
Dialogue: 0,0:02:57.61,0:02:57.88,Default,,0000,0000,0000,,
Dialogue: 0,0:02:57.88,0:03:01.36,Default,,0000,0000,0000,,이 상황에서 x 가 어떤 값을 가져야 할지 \N알아낼 수 있어요
Dialogue: 0,0:03:01.36,0:03:01.62,Default,,0000,0000,0000,,
Dialogue: 0,0:03:01.62,0:03:03.21,Default,,0000,0000,0000,,암산으로도 할 수 있어요
Dialogue: 0,0:03:03.21,0:03:06.15,Default,,0000,0000,0000,,무엇에다가 3을 더하면 1이 될까요?
Dialogue: 0,0:03:06.15,0:03:06.43,Default,,0000,0000,0000,,
Dialogue: 0,0:03:06.43,0:03:10.02,Default,,0000,0000,0000,,x가 -2라면 3을 더하면 1이 되겠죠
Dialogue: 0,0:03:10.02,0:03:14.80,Default,,0000,0000,0000,,방정식이 변수의 값을 결정하는 거에요
Dialogue: 0,0:03:14.80,0:03:15.13,Default,,0000,0000,0000,,
Dialogue: 0,0:03:15.13,0:03:18.37,Default,,0000,0000,0000,,그렇지만 무조건적으로 결정하는 건 아니에요
Dialogue: 0,0:03:18.37,0:03:18.93,Default,,0000,0000,0000,,예를 들면
Dialogue: 0,0:03:18.93,0:03:25.73,Default,,0000,0000,0000,,x + y + z = 5
Dialogue: 0,0:03:25.73,0:03:27.78,Default,,0000,0000,0000,,이 방정식에서 좌변은
Dialogue: 0,0:03:27.78,0:03:29.37,Default,,0000,0000,0000,,우변과 값이 같죠
Dialogue: 0,0:03:29.37,0:03:31.64,Default,,0000,0000,0000,,5는 우변에만 있어요
Dialogue: 0,0:03:31.64,0:03:33.78,Default,,0000,0000,0000,,여기에는 몇 가지 제약이 있어요
Dialogue: 0,0:03:33.78,0:03:36.05,Default,,0000,0000,0000,,y와 z를 알면 x의 값이 정해져요
Dialogue: 0,0:03:36.05,0:03:36.31,Default,,0000,0000,0000,,
Dialogue: 0,0:03:36.31,0:03:38.23,Default,,0000,0000,0000,,만약 x와 y를 알려준다면
Dialogue: 0,0:03:38.23,0:03:39.92,Default,,0000,0000,0000,,z가 결정되겠죠
Dialogue: 0,0:03:39.92,0:03:43.10,Default,,0000,0000,0000,,다른 것들이 어떤 가에 달려 있는 거에요
Dialogue: 0,0:03:43.10,0:03:44.06,Default,,0000,0000,0000,,예를 들면
Dialogue: 0,0:03:44.06,0:03:51.64,Default,,0000,0000,0000,,만약 y가 3이고 z가 2라면
Dialogue: 0,0:03:51.64,0:03:53.76,Default,,0000,0000,0000,,x는 얼마일까요?
Dialogue: 0,0:03:53.76,0:03:58.32,Default,,0000,0000,0000,,y가 3이고 z가 2이면
Dialogue: 0,0:03:58.32,0:03:58.61,Default,,0000,0000,0000,,
Dialogue: 0,0:03:58.61,0:04:00.49,Default,,0000,0000,0000,,좌변은
Dialogue: 0,0:04:00.49,0:04:02.15,Default,,0000,0000,0000,,x + 3 + 2니까
Dialogue: 0,0:04:02.15,0:04:04.100,Default,,0000,0000,0000,,x + 5가 되고
Dialogue: 0,0:04:04.100,0:04:06.81,Default,,0000,0000,0000,,우변은 5가 되서
Dialogue: 0,0:04:06.81,0:04:08.98,Default,,0000,0000,0000,,x + 5 = 5라는 것을 구할 수 있을 거에요
Dialogue: 0,0:04:08.98,0:04:12.38,Default,,0000,0000,0000,,그러면 무엇에다가 5를 더하면 5가 될까요?
Dialogue: 0,0:04:12.38,0:04:12.63,Default,,0000,0000,0000,,
Dialogue: 0,0:04:12.63,0:04:16.68,Default,,0000,0000,0000,,x는 0이 되어야 한다고 결정짓는 거에요
Dialogue: 0,0:04:16.68,0:04:16.94,Default,,0000,0000,0000,,
Dialogue: 0,0:04:16.94,0:04:18.24,Default,,0000,0000,0000,,그런데 중요한 사실이 있죠
Dialogue: 0,0:04:18.24,0:04:19.79,Default,,0000,0000,0000,,식과 방정식의 차이점을
Dialogue: 0,0:04:19.79,0:04:20.80,Default,,0000,0000,0000,,알고 있어야 해요
Dialogue: 0,0:04:20.80,0:04:23.36,Default,,0000,0000,0000,,방정식은 단순히 두 개의 식을 같다고 놓는 거에요
Dialogue: 0,0:04:23.36,0:04:23.67,Default,,0000,0000,0000,,
Dialogue: 0,0:04:23.67,0:04:25.37,Default,,0000,0000,0000,,여기서 알 수 있는 중요한 사실은
Dialogue: 0,0:04:25.37,0:04:31.97,Default,,0000,0000,0000,,변수는 문제의 조건에 따라서 \N값이 달라질 수 있다는 거에요
Dialogue: 0,0:04:31.97,0:04:32.32,Default,,0000,0000,0000,,
Dialogue: 0,0:04:32.32,0:04:32.64,Default,,0000,0000,0000,,
Dialogue: 0,0:04:32.64,0:04:37.77,Default,,0000,0000,0000,,변수들이 다른 값을 가지는 식을 계산해 볼게요
Dialogue: 0,0:04:37.77,0:04:38.06,Default,,0000,0000,0000,,
Dialogue: 0,0:04:38.06,0:04:41.60,Default,,0000,0000,0000,,예를 들어
Dialogue: 0,0:04:41.60,0:04:48.10,Default,,0000,0000,0000,,x의 y제곱 이라는 식이 있다고 해요
Dialogue: 0,0:04:48.10,0:04:48.42,Default,,0000,0000,0000,,
Dialogue: 0,0:04:48.42,0:04:51.96,Default,,0000,0000,0000,,x는 5이고
Dialogue: 0,0:04:51.96,0:04:55.50,Default,,0000,0000,0000,,y는 2라고 하면
Dialogue: 0,0:04:55.50,0:04:55.79,Default,,0000,0000,0000,,
Dialogue: 0,0:04:55.79,0:04:58.91,Default,,0000,0000,0000,,이 식은
Dialogue: 0,0:04:58.91,0:05:01.51,Default,,0000,0000,0000,,x가 5이고
Dialogue: 0,0:05:01.51,0:05:02.89,Default,,0000,0000,0000,,x가 5이고
Dialogue: 0,0:05:02.89,0:05:04.36,Default,,0000,0000,0000,,y가 2이니까
Dialogue: 0,0:05:04.36,0:05:06.61,Default,,0000,0000,0000,,5의 제곱이 되서
Dialogue: 0,0:05:06.61,0:05:08.15,Default,,0000,0000,0000,,답은
Dialogue: 0,0:05:08.15,0:05:09.78,Default,,0000,0000,0000,,25에요
Dialogue: 0,0:05:09.78,0:05:12.70,Default,,0000,0000,0000,,값을 바꿔서
Dialogue: 0,0:05:12.70,0:05:15.97,Default,,0000,0000,0000,,x가
Dialogue: 0,0:05:15.97,0:05:16.29,Default,,0000,0000,0000,,
Dialogue: 0,0:05:16.29,0:05:20.96,Default,,0000,0000,0000,,x가 -2이고
Dialogue: 0,0:05:20.96,0:05:24.77,Default,,0000,0000,0000,,y가 3이라면
Dialogue: 0,0:05:24.77,0:05:27.84,Default,,0000,0000,0000,,이 식은
Dialogue: 0,0:05:27.84,0:05:30.47,Default,,0000,0000,0000,,
Dialogue: 0,0:05:30.47,0:05:32.39,Default,,0000,0000,0000,,이 식에서
Dialogue: 0,0:05:32.39,0:05:33.96,Default,,0000,0000,0000,,이렇게 조건이 주어진다면
Dialogue: 0,0:05:33.96,0:05:36.70,Default,,0000,0000,0000,,x 대신 -2를 쓰고
Dialogue: 0,0:05:36.70,0:05:38.17,Default,,0000,0000,0000,,y는 3이니까
Dialogue: 0,0:05:38.17,0:05:42.08,Default,,0000,0000,0000,,-2의 세제곱이라서
Dialogue: 0,0:05:42.08,0:05:44.58,Default,,0000,0000,0000,,-2 x -2 x -2는
Dialogue: 0,0:05:44.58,0:05:46.90,Default,,0000,0000,0000,,-8이 되겠네요
Dialogue: 0,0:05:46.90,0:05:48.57,Default,,0000,0000,0000,,-2 곱하기 -2는 4이고
Dialogue: 0,0:05:48.57,0:05:52.15,Default,,0000,0000,0000,,-2를 또 곱하면 -8이 되요
Dialogue: 0,0:05:52.15,0:05:53.37,Default,,0000,0000,0000,,답은 -8이에요
Dialogue: 0,0:05:53.37,0:05:55.71,Default,,0000,0000,0000,,변수들의 값에 따라서
Dialogue: 0,0:05:55.71,0:05:59.28,Default,,0000,0000,0000,,더 어려운 것들도 계산할 수 있어요
Dialogue: 0,0:05:59.28,0:05:59.68,Default,,0000,0000,0000,,
Dialogue: 0,0:05:59.68,0:06:06.61,Default,,0000,0000,0000,,√(x+y) - x 같은 것들 말이에요
Dialogue: 0,0:06:06.61,0:06:11.88,Default,,0000,0000,0000,,x가 1이고
Dialogue: 0,0:06:11.88,0:06:16.01,Default,,0000,0000,0000,,y가 8이라고 하면
Dialogue: 0,0:06:16.01,0:06:18.13,Default,,0000,0000,0000,,이 식에서
Dialogue: 0,0:06:18.13,0:06:21.42,Default,,0000,0000,0000,,x가 보일 때마다 그 자리에 1을 넣어주면 되요
Dialogue: 0,0:06:21.42,0:06:23.01,Default,,0000,0000,0000,,여기에도 1을 대입하고
Dialogue: 0,0:06:23.01,0:06:24.81,Default,,0000,0000,0000,,여기에도 1을 대입하면 되겠네요
Dialogue: 0,0:06:24.81,0:06:26.75,Default,,0000,0000,0000,,y가 보일 때마다
Dialogue: 0,0:06:26.75,0:06:29.25,Default,,0000,0000,0000,,그 자리에 8을 넣어주면 되는 거죠
Dialogue: 0,0:06:29.25,0:06:31.80,Default,,0000,0000,0000,,이 식에서는 변수 대신에 8이 보이게 쓰는 거에요
Dialogue: 0,0:06:31.80,0:06:32.09,Default,,0000,0000,0000,,
Dialogue: 0,0:06:32.09,0:06:34.61,Default,,0000,0000,0000,,근호 안에 1+ 8이 있게 되요
Dialogue: 0,0:06:34.61,0:06:37.82,Default,,0000,0000,0000,,9의 양의 제곱근은 3이죠
Dialogue: 0,0:06:37.82,0:06:40.50,Default,,0000,0000,0000,,모든 것들이 간단해져요
Dialogue: 0,0:06:40.50,0:06:43.12,Default,,0000,0000,0000,,이 식에서 변수들의 값을 이렇게 정하면
Dialogue: 0,0:06:43.12,0:06:45.59,Default,,0000,0000,0000,,이 식은 3으로 간단하게 되요
Dialogue: 0,0:06:45.59,0:06:46.50,Default,,0000,0000,0000,,1 + 8 = 9
Dialogue: 0,0:06:46.50,0:06:48.68,Default,,0000,0000,0000,,9의 양의 제곱근은 3이고
Dialogue: 0,0:06:48.68,0:06:50.77,Default,,0000,0000,0000,,3 빼기 1은
Dialogue: 0,0:06:50.77,0:06:54.58,Default,,0000,0000,0000,,2가 되겠네요