[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.60,0:00:02.34,Default,,0000,0000,0000,,Se facciamo aritmetica di base,
Dialogue: 0,0:00:02.34,0:00:04.59,Default,,0000,0000,0000,,vediamo i numeri concreti.
Dialogue: 0,0:00:04.59,0:00:07.41,Default,,0000,0000,0000,,Per esempio 23 + 5.
Dialogue: 0,0:00:07.41,0:00:08.72,Default,,0000,0000,0000,,Sappiamo che sono questi numeri\Ne li possiamo calcolare.
Dialogue: 0,0:00:08.72,0:00:10.00,Default,,0000,0000,0000,,
Dialogue: 0,0:00:10.00,0:00:11.66,Default,,0000,0000,0000,,In tutto fa 28.
Dialogue: 0,0:00:11.66,0:00:13.90,Default,,0000,0000,0000,,Possiamo dire 2 x 7.
Dialogue: 0,0:00:13.90,0:00:17.48,Default,,0000,0000,0000,,Possiamo dire 3 diviso 4.
Dialogue: 0,0:00:17.48,0:00:19.06,Default,,0000,0000,0000,,In questi casi sappiamo esattamente\Ndi che numeri stiamo parlando.
Dialogue: 0,0:00:19.06,0:00:20.87,Default,,0000,0000,0000,,
Dialogue: 0,0:00:20.87,0:00:23.78,Default,,0000,0000,0000,,Entrando nel mondo dell'algebra
Dialogue: 0,0:00:23.78,0:00:25.87,Default,,0000,0000,0000,,(e forse l'avete già visto\Nda qualche parte)
Dialogue: 0,0:00:25.87,0:00:30.05,Default,,0000,0000,0000,,cominciamo a parlare di variabili.
Dialogue: 0,0:00:30.05,0:00:31.53,Default,,0000,0000,0000,,Ci sono molti in modi in cui si può\Npensare alle variabili.
Dialogue: 0,0:00:31.53,0:00:32.28,Default,,0000,0000,0000,,
Dialogue: 0,0:00:32.28,0:00:34.50,Default,,0000,0000,0000,,In realtà sono solo numeri\Nin delle espressioni
Dialogue: 0,0:00:34.50,0:00:36.25,Default,,0000,0000,0000,,in cui possono cambiare.
Dialogue: 0,0:00:36.25,0:00:38.14,Default,,0000,0000,0000,,I valori in quelle espressioni\Npossono variare.
Dialogue: 0,0:00:38.14,0:00:42.20,Default,,0000,0000,0000,,Per esempio, se scrivo "x + 5".
Dialogue: 0,0:00:42.20,0:00:44.78,Default,,0000,0000,0000,,
Dialogue: 0,0:00:44.78,0:00:46.65,Default,,0000,0000,0000,,Questa è un'espressione.
Dialogue: 0,0:00:46.65,0:00:48.30,Default,,0000,0000,0000,,Il valore di questa cambia\Na seconda del valore della x.
Dialogue: 0,0:00:48.30,0:00:51.47,Default,,0000,0000,0000,,
Dialogue: 0,0:00:51.47,0:00:56.66,Default,,0000,0000,0000,,Se x è uguale a 1,
Dialogue: 0,0:00:56.66,0:01:01.72,Default,,0000,0000,0000,,allora x più 5 (questa espressione)
Dialogue: 0,0:01:01.72,0:01:06.05,Default,,0000,0000,0000,,sarà uguale a 1 (perchè ora x è 1)\Nsarà uguale a 1 più 5.
Dialogue: 0,0:01:06.05,0:01:07.07,Default,,0000,0000,0000,,
Dialogue: 0,0:01:07.07,0:01:08.32,Default,,0000,0000,0000,,
Dialogue: 0,0:01:08.32,0:01:11.10,Default,,0000,0000,0000,,Quindi x + 5 sarà uguale a 6.
Dialogue: 0,0:01:11.10,0:01:16.82,Default,,0000,0000,0000,,Se la x è uguale, per esempio, a -7,\Nallora x + 5 sarà uguale a -
Dialogue: 0,0:01:16.82,0:01:22.18,Default,,0000,0000,0000,,
Dialogue: 0,0:01:22.18,0:01:24.12,Default,,0000,0000,0000,,Beh, ora x è -7
Dialogue: 0,0:01:24.12,0:01:28.84,Default,,0000,0000,0000,,Quindi sarà -7 + 5, che fa -2.
Dialogue: 0,0:01:28.84,0:01:29.44,Default,,0000,0000,0000,,
Dialogue: 0,0:01:29.44,0:01:34.02,Default,,0000,0000,0000,,Quindi, la x qui è una variabile,
Dialogue: 0,0:01:34.02,0:01:37.70,Default,,0000,0000,0000,,e il suo valore può cambiare\Na seconda del contesto.
Dialogue: 0,0:01:37.70,0:01:39.95,Default,,0000,0000,0000,,E qui stiamo parlando di un'espressione.
Dialogue: 0,0:01:39.95,0:01:42.17,Default,,0000,0000,0000,,Si può anche trovare in un'equazione.
Dialogue: 0,0:01:42.17,0:01:44.30,Default,,0000,0000,0000,,È importante capire la differenza\Ntra un'espressione e un'equazione.
Dialogue: 0,0:01:44.30,0:01:46.90,Default,,0000,0000,0000,,
Dialogue: 0,0:01:46.90,0:01:49.83,Default,,0000,0000,0000,,Un'espressione è solo la dichiarazione\Ndi un valore, di qualche quantità.
Dialogue: 0,0:01:49.83,0:01:51.73,Default,,0000,0000,0000,,
Dialogue: 0,0:01:51.73,0:01:54.33,Default,,0000,0000,0000,,Quindi questa è un'espressione.
Dialogue: 0,0:01:54.33,0:01:56.64,Default,,0000,0000,0000,,Un'espressione sarebbe, per esempio,
Dialogue: 0,0:01:56.64,0:01:57.98,Default,,0000,0000,0000,,beh, quella che abbiamo visto: x + 5
Dialogue: 0,0:01:57.98,0:01:59.26,Default,,0000,0000,0000,,
Dialogue: 0,0:01:59.26,0:02:01.05,Default,,0000,0000,0000,,Il valore di questa espressione cambierà\Na seconda del valore di questa variabile.
Dialogue: 0,0:02:01.05,0:02:05.74,Default,,0000,0000,0000,,
Dialogue: 0,0:02:05.74,0:02:09.06,Default,,0000,0000,0000,,E si può calcolare a seconda\Ndei diversi valori della x.
Dialogue: 0,0:02:09.06,0:02:11.27,Default,,0000,0000,0000,,Un'altra espressione potrebbe essere,\Nper esempio, y + z.
Dialogue: 0,0:02:11.27,0:02:13.15,Default,,0000,0000,0000,,
Dialogue: 0,0:02:13.15,0:02:14.34,Default,,0000,0000,0000,,Ora tutto è una variabile
Dialogue: 0,0:02:14.34,0:02:16.55,Default,,0000,0000,0000,,Se la y è 1 e la z è 2, sarà 1 + 2.\N
Dialogue: 0,0:02:16.55,0:02:18.56,Default,,0000,0000,0000,,
Dialogue: 0,0:02:18.56,0:02:21.39,Default,,0000,0000,0000,,Se la y è 0 e la z è -1, sarà 0 + (-1).
Dialogue: 0,0:02:21.39,0:02:24.07,Default,,0000,0000,0000,,
Dialogue: 0,0:02:24.07,0:02:25.90,Default,,0000,0000,0000,,Queste possono essere calcolate\Ne ci daranno un valore
Dialogue: 0,0:02:25.90,0:02:27.42,Default,,0000,0000,0000,,
Dialogue: 0,0:02:27.42,0:02:30.81,Default,,0000,0000,0000,,a seconda di ognuna delle variabili\Nche ci sono nell'espressione.
Dialogue: 0,0:02:30.81,0:02:32.33,Default,,0000,0000,0000,,
Dialogue: 0,0:02:32.33,0:02:34.28,Default,,0000,0000,0000,,In una equazione, fissiamo\Nle espressioni come uguali tra di loro.
Dialogue: 0,0:02:34.28,0:02:35.47,Default,,0000,0000,0000,,
Dialogue: 0,0:02:35.47,0:02:38.10,Default,,0000,0000,0000,,Per questo si chiamano "equazioni".
Dialogue: 0,0:02:38.10,0:02:40.12,Default,,0000,0000,0000,,Stiamo uguagliando due cose.
Dialogue: 0,0:02:40.12,0:02:42.92,Default,,0000,0000,0000,,In un'equazione, c'è un'espressione\Nuguale a un'altra espressione.
Dialogue: 0,0:02:42.92,0:02:44.64,Default,,0000,0000,0000,,
Dialogue: 0,0:02:44.64,0:02:47.87,Default,,0000,0000,0000,,Per esempio, potremmo dire\Nqualcosa come x + 3 = 1.
Dialogue: 0,0:02:47.87,0:02:52.06,Default,,0000,0000,0000,,
Dialogue: 0,0:02:52.06,0:02:54.46,Default,,0000,0000,0000,,E in questa situazione in cui\Nc'è un'equazione con una sola incognita,
Dialogue: 0,0:02:54.46,0:02:57.88,Default,,0000,0000,0000,,
Dialogue: 0,0:02:57.88,0:02:59.27,Default,,0000,0000,0000,,Si può davvero scoprire cosa\Ndeve essere la x in questa situazione.
Dialogue: 0,0:02:59.27,0:03:01.62,Default,,0000,0000,0000,,
Dialogue: 0,0:03:01.62,0:03:03.21,Default,,0000,0000,0000,,E potresti farlo anche a mente.
Dialogue: 0,0:03:03.21,0:03:05.33,Default,,0000,0000,0000,,Qual è il numero che addizionato a 2 fa 1?
Dialogue: 0,0:03:05.33,0:03:06.43,Default,,0000,0000,0000,,Beh, si può fare a mente.
Dialogue: 0,0:03:06.43,0:03:08.87,Default,,0000,0000,0000,,Se ho meno 2, -2 più 3 è uguale a 1.
Dialogue: 0,0:03:08.87,0:03:12.03,Default,,0000,0000,0000,,In questo contesto, l'equazione limita\Nil valore che questa variabile può avere.
Dialogue: 0,0:03:12.03,0:03:15.13,Default,,0000,0000,0000,,
Dialogue: 0,0:03:15.13,0:03:17.41,Default,,0000,0000,0000,,Ma non deve per forza limitare così tanto.
Dialogue: 0,0:03:17.41,0:03:18.93,Default,,0000,0000,0000,,Potrebbe esserci qualcosa come\Nx + y + z = 5.
Dialogue: 0,0:03:18.93,0:03:25.73,Default,,0000,0000,0000,,
Dialogue: 0,0:03:25.73,0:03:27.78,Default,,0000,0000,0000,,Ora, questa espressione\Nè uguale a quest'altra.
Dialogue: 0,0:03:27.78,0:03:29.37,Default,,0000,0000,0000,,
Dialogue: 0,0:03:29.37,0:03:31.64,Default,,0000,0000,0000,,5 in realtà è un'espressione qui.
Dialogue: 0,0:03:31.64,0:03:32.90,Default,,0000,0000,0000,,E ci sono delle limitazioni.
Dialogue: 0,0:03:32.90,0:03:35.00,Default,,0000,0000,0000,,Se qualcuno ci dicesse\Ncosa sono la y e la z,
Dialogue: 0,0:03:35.00,0:03:36.31,Default,,0000,0000,0000,,questo limiterebbe la x.
Dialogue: 0,0:03:36.31,0:03:38.23,Default,,0000,0000,0000,,Se qualcuno ci dicesse\Ncosa sono la x e la y,
Dialogue: 0,0:03:38.23,0:03:39.92,Default,,0000,0000,0000,,questo limiterebbe la z.
Dialogue: 0,0:03:39.92,0:03:42.38,Default,,0000,0000,0000,,Ma dipende da quanto valgono\Nle diverse variabili.
Dialogue: 0,0:03:42.38,0:03:44.06,Default,,0000,0000,0000,,Per esempio, se dicessimo y=3 e z=2
Dialogue: 0,0:03:44.06,0:03:51.64,Default,,0000,0000,0000,,quale sarebbe la x?
Dialogue: 0,0:03:51.64,0:03:53.39,Default,,0000,0000,0000,,
Dialogue: 0,0:03:53.39,0:03:58.10,Default,,0000,0000,0000,,Quindi, se y=3 e z=2, allora\Nl'espressione a sinistra sarebbe
Dialogue: 0,0:03:58.10,0:03:58.61,Default,,0000,0000,0000,,
Dialogue: 0,0:03:58.61,0:04:00.49,Default,,0000,0000,0000,,
Dialogue: 0,0:04:00.49,0:04:02.15,Default,,0000,0000,0000,,x + 3 + 5, cioè x + 5
Dialogue: 0,0:04:02.15,0:04:04.100,Default,,0000,0000,0000,,
Dialogue: 0,0:04:04.100,0:04:06.81,Default,,0000,0000,0000,,Questa parte sarebbe uguale a 5.
Dialogue: 0,0:04:06.81,0:04:08.98,Default,,0000,0000,0000,,x + 5 = 5.
Dialogue: 0,0:04:08.98,0:04:11.20,Default,,0000,0000,0000,,E cosa più 5 fa 5?
Dialogue: 0,0:04:11.20,0:04:12.63,Default,,0000,0000,0000,,Beh, ora stiamo limitando\Nla x ad essere per forza 0.
Dialogue: 0,0:04:12.63,0:04:14.38,Default,,0000,0000,0000,,
Dialogue: 0,0:04:14.38,0:04:16.94,Default,,0000,0000,0000,,
Dialogue: 0,0:04:16.94,0:04:18.24,Default,,0000,0000,0000,,Ma il punto importante qui
Dialogue: 0,0:04:18.24,0:04:19.79,Default,,0000,0000,0000,,è, per prima cosa, capire la differenza\Ntra un'espressione e un'equazione.
Dialogue: 0,0:04:19.79,0:04:20.80,Default,,0000,0000,0000,,
Dialogue: 0,0:04:20.80,0:04:21.85,Default,,0000,0000,0000,,In un'equazione,
Dialogue: 0,0:04:21.85,0:04:23.67,Default,,0000,0000,0000,,si equivalgono due espressioni.
Dialogue: 0,0:04:23.67,0:04:25.37,Default,,0000,0000,0000,,
Dialogue: 0,0:04:25.37,0:04:27.99,Default,,0000,0000,0000,,
Dialogue: 0,0:04:27.99,0:04:31.36,Default,,0000,0000,0000,,
Dialogue: 0,0:04:31.36,0:04:32.78,Default,,0000,0000,0000,,
Dialogue: 0,0:04:32.78,0:04:35.22,Default,,0000,0000,0000,,
Dialogue: 0,0:04:35.22,0:04:38.06,Default,,0000,0000,0000,,
Dialogue: 0,0:04:38.06,0:04:41.60,Default,,0000,0000,0000,,
Dialogue: 0,0:04:41.60,0:04:43.31,Default,,0000,0000,0000,,
Dialogue: 0,0:04:43.31,0:04:47.80,Default,,0000,0000,0000,,
Dialogue: 0,0:04:47.80,0:04:51.96,Default,,0000,0000,0000,,
Dialogue: 0,0:04:51.96,0:04:54.31,Default,,0000,0000,0000,,
Dialogue: 0,0:04:54.31,0:04:55.79,Default,,0000,0000,0000,,
Dialogue: 0,0:04:55.79,0:04:58.91,Default,,0000,0000,0000,,
Dialogue: 0,0:04:58.91,0:05:01.51,Default,,0000,0000,0000,,
Dialogue: 0,0:05:01.51,0:05:02.89,Default,,0000,0000,0000,,
Dialogue: 0,0:05:02.89,0:05:04.36,Default,,0000,0000,0000,,
Dialogue: 0,0:05:04.36,0:05:06.61,Default,,0000,0000,0000,,
Dialogue: 0,0:05:06.61,0:05:08.15,Default,,0000,0000,0000,,
Dialogue: 0,0:05:08.15,0:05:09.78,Default,,0000,0000,0000,,
Dialogue: 0,0:05:09.78,0:05:11.63,Default,,0000,0000,0000,,
Dialogue: 0,0:05:11.63,0:05:14.36,Default,,0000,0000,0000,,
Dialogue: 0,0:05:14.36,0:05:16.29,Default,,0000,0000,0000,,
Dialogue: 0,0:05:16.29,0:05:20.96,Default,,0000,0000,0000,,
Dialogue: 0,0:05:20.96,0:05:24.77,Default,,0000,0000,0000,,
Dialogue: 0,0:05:24.77,0:05:27.84,Default,,0000,0000,0000,,
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,,
Dialogue: 0,0:05:32.39,0:05:35.38,Default,,0000,0000,0000,,
Dialogue: 0,0:05:35.38,0:05:36.70,Default,,0000,0000,0000,,
Dialogue: 0,0:05:36.70,0:05:38.17,Default,,0000,0000,0000,,
Dialogue: 0,0:05:38.17,0:05:42.08,Default,,0000,0000,0000,,
Dialogue: 0,0:05:42.08,0:05:44.58,Default,,0000,0000,0000,,
Dialogue: 0,0:05:44.58,0:05:46.90,Default,,0000,0000,0000,,
Dialogue: 0,0:05:46.90,0:05:48.57,Default,,0000,0000,0000,,
Dialogue: 0,0:05:48.57,0:05:52.15,Default,,0000,0000,0000,,
Dialogue: 0,0:05:52.15,0:05:53.37,Default,,0000,0000,0000,,
Dialogue: 0,0:05:53.37,0:05:55.71,Default,,0000,0000,0000,,
Dialogue: 0,0:05:55.71,0:05:58.28,Default,,0000,0000,0000,,
Dialogue: 0,0:05:58.28,0:05:59.68,Default,,0000,0000,0000,,
Dialogue: 0,0:05:59.68,0:06:06.61,Default,,0000,0000,0000,,
Dialogue: 0,0:06:06.61,0:06:11.88,Default,,0000,0000,0000,,
Dialogue: 0,0:06:11.88,0:06:16.01,Default,,0000,0000,0000,,
Dialogue: 0,0:06:16.01,0:06:18.57,Default,,0000,0000,0000,,
Dialogue: 0,0:06:18.57,0:06:21.42,Default,,0000,0000,0000,,
Dialogue: 0,0:06:21.42,0:06:23.01,Default,,0000,0000,0000,,
Dialogue: 0,0:06:23.01,0:06:24.81,Default,,0000,0000,0000,,
Dialogue: 0,0:06:24.81,0:06:26.75,Default,,0000,0000,0000,,
Dialogue: 0,0:06:26.75,0:06:28.41,Default,,0000,0000,0000,,
Dialogue: 0,0:06:28.41,0:06:30.82,Default,,0000,0000,0000,,
Dialogue: 0,0:06:30.82,0:06:32.09,Default,,0000,0000,0000,,
Dialogue: 0,0:06:32.09,0:06:34.61,Default,,0000,0000,0000,,
Dialogue: 0,0:06:34.61,0:06:37.82,Default,,0000,0000,0000,,
Dialogue: 0,0:06:37.82,0:06:40.97,Default,,0000,0000,0000,,
Dialogue: 0,0:06:40.97,0:06:43.12,Default,,0000,0000,0000,,
Dialogue: 0,0:06:43.12,0:06:45.59,Default,,0000,0000,0000,,
Dialogue: 0,0:06:45.59,0:06:46.50,Default,,0000,0000,0000,,
Dialogue: 0,0:06:46.50,0:06:48.68,Default,,0000,0000,0000,,
Dialogue: 0,0:06:48.68,0:06:50.77,Default,,0000,0000,0000,,
Dialogue: 0,0:06:50.77,0:06:54.77,Default,,0000,0000,0000,,