Геометрическая прогрессия
- 1. óðîê-ïðåçåíòàöèÿ Ãåîìåòðè÷åñêàÿ ïðîãðåññèÿ øêîëà òàêàÿ-òî Ïîñïåëîâà Ì. Ä. Ìîñêâà 2015
- 2. Çàäà÷à î ç¼ðíàõ íà øàõìàòíîé äîñêå Îïèñàíèå çàäà÷è â Âèêèïåäèè 1 2 22 23 24 25 26 27 28 29 210 211 212 213 214 215 . . . 256 257 258 259 260 261 262 263 Îáùåå ÷èñëî ç¼ðåí S = 1 + 2 + 22 + 23 + . . . + 262 + 263
- 3. Ãåîìåòðè÷åñêàÿ ïðîãðåññèÿ Îïðåäåëåíèå Ãåîìåòðè÷åñêîé ïðîãðåññèåé íàçûâàåòñÿ ïîñëåäîâàòåëüíîñòü îòëè÷íûõ îò íóëÿ ÷èñåë, êàæäûé ÷ëåí êîòîðîé, íà÷èíàÿ ñî âòîðîãî, ðàâåí ïðåäûäóùåìó ÷ëåíó, óìíîæåííîìó íà îäíî è òî æå ÷èñëî.
- 4. Ãåîìåòðè÷åñêàÿ ïðîãðåññèÿ Ïîñëåäîâàòåëüíîñòü (bn) ãåîìåòðè÷åñêàÿ ïðîãðåññèÿ, åñëè äëÿ ëþáîãî n ∈ N âûïîëíÿåòñÿ bn = 0 nn+1 = bn · q ãäå q íåêîòîðîå ÷èñëî
- 5. Çíàìåíàòåëü Ïðè ëþáîì n ∈ N bn+1 bn = q Îïðåäåëåíèå ×èñëî q íàçûâàåòñÿ çíàìåíàòåëåì ãåîìåòðè÷åñêîé ïðîãðåññèè
- 6. Ïðèìåðû 1. b1 = 6, q = 2 çàäàþò ïðîãðåññèþ 6, 12, 24, 48, 96, . . . 2. b1 = 1, q = 0.1 çàäàþò ïðîãðåññèþ 1, 0.1, 0.01, 0.001, 0.0001, . . .
- 7. Ôîðìóëà n-ãî ýëåìåíòà ãåîìåòðè÷åñêîé ïðîãðåññèè bn = bn−1 · q b2 = b1 · q b3 = b2 · q = b1 · q2 b4 = b3 · q = b1 · q3 . . . Ôîðìóëà n-ãî ýëåìåíòà bn = b1 · qn−1
- 8. Õàðàêòåðèñòè÷åñêîå ñâîéñòâî ãåîìåòðè÷åñêîé ïðîãðåññèè bn−1 · bn+1 = b2 n îòêóäà Õàðàêòåðèñòè÷åñêîå ñâîéñòâî |bn| = bn−1bn+1
- 9. Ôîðìóëà ñóììû n ïåðâûõ ÷ëåíîâ ãåîìåòðè÷åñêîé ïðîãðåññèè Sn = bnq − b1 q − 1 èëè Ôîðìóëà ñóììû Sn = b1(qn − 1) q − 1 ïðè q = 1
- 10. Ôîðìóëà ñóììû áåñêîíå÷íî óáûâàþùåé ãåîìåòðè÷åñêîé ïðîãðåññèè Ïðè |q| 1: Sn = b1(qn − 1) q − 1 = b1qn − b1 q − 1 = b1 − b1qn 1 − q = b1 1 − q − b1 1 − q ·qn Ïðè n → ∞ S → b1 1 − q Ôîðìóëà ñóììû S = b1 1 − q ×èñëî S íàçûâàþò ñóììîé áåñêîíå÷íî óáûâàþùåé ãåîìåòðè÷åñêîé ïðîãðåññèè.
- 11. Ïðèìåðû ãåîìåòðè÷åñêèõ ïðîãðåññèé Áàíêîâñêèé âêëàä b1 ñóììà âêëàäà, q ïðîöåíò Ïîñëåäîâàòåëüíîñòü ïëîùàäåé êâàäðàòîâ, ãäå êàæäûé ñëåäóþùèé êâàäðàò ïîëó÷àåòñÿ ñîåäèíåíèåì ñåðåäèí ñòîðîí ïðåäûäóùåãî áåñêîíå÷íàÿ ãåîìåòðè÷åñêàÿ ïðîãðåññèÿ ñî çíàìåíàòåëåì 1/2