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Ðîçâ’ÿçàííÿ. Øëÿõîì ïåðåòâîðåíü Ãàóññà îòðèìàºìî<br />

æ1 1 1 5ö æ1 1 1 5ö<br />

æ1 1 1 5ö<br />

2 1 1 4 0 3 3 6<br />

- - : - - - :<br />

3 0 0 9<br />

çè ÷ ø.<br />

çè2 2 2 10ø ÷ è ç0 0 0 0ø<br />

÷<br />

Íåõàé òåïåð õ 3 = ñ, äå ñ — äîâ³ëüíà ñòàëà. Òîä³ ðîçâ’ÿçîê<br />

äàíî¿ ñèñòåìè ìຠòàêèé âèãëÿä:<br />

(x 1 = 3; x 2 =2− c; x 3 = c).<br />

ßñíî, ùî çà ðàõóíîê äîâ³ëüíîñò³ ñòàëî¿ ñ ðîçãëÿíóòå ð³âíÿííÿ<br />

ìຠíåñê³í÷åííó ìíîæèíó ðîçâ’ÿçê³â.<br />

Òóò òåîðåìà Êðîíåêåðà–Êàïåëë³ òåæ ãàðíî ïðàöþº:<br />

rang A = rang A*=2.<br />

Ïðèêëàä 3.5.4. Íåõàé ôàáðèêà âèðîáëÿº äèòÿ÷å, æ³íî÷å<br />

³ ÷îëîâ³÷å âçóòòÿ. Ïðè öüîìó âèêîðèñòîâóºòüñÿ ñèðîâèíà<br />

òðüîõ âèä³â: Q 1 , Q 2 , Q 3 . Íàïðèêëàä, Q 1 ìîæå áóòè ñèðîâèíîþ<br />

ç íàòóðàëüíî¿ øê³ðè; Q 2 — ñèðîâèíîþ äëÿ âèãîòîâëåííÿ<br />

ï³äîøâ; Q 3 — ñèðîâèíîþ äëÿ âèãîòîâëåííÿ øíóðê³â. Íîðìè<br />

çàòðàò (â óìîâíèõ îäèíèöÿõ) êîæíî¿ ç íèõ íà îäíó ïàðó<br />

âçóòòÿ òà îáñÿã çàòðàò ñèðîâèíè íà 1 äåíü çàäàí³ ó âèãëÿä³<br />

ìàòðèö³ A òà âåêòîðà-ñòîâïöÿ b:<br />

æ1 2 3ö æ1300ö<br />

A= 1 3 4 , 1700<br />

b=<br />

.<br />

çè1 2 5 ÷ ø è ç1700ø<br />

÷<br />

Òóò ïåðøèé ðÿäîê ìàòðèö³ îçíà÷àº, ùî íà äèòÿ÷å, æ³íî÷å<br />

³ ÷îëîâ³÷å âçóòòÿ çà 1 äåíü âèòðà÷àºòüñÿ â³äïîâ³äíî îäíà<br />

îäèíèöÿ, äâ³ îäèíèö³ ³ òðè îäèíèö³ ñèðîâèíè Q 1 . Àíàëîã³÷íèé<br />

ñìèñë ìຠäðóãèé òà òðåò³é ðÿäîê. Ïðè öüîìó âåêòîðñòîâïåöü<br />

âèçíà÷ຠîáñÿã çàòðàò ñèðîâèíè çà 1 äåíü.<br />

Òðåáà çíàéòè ùîäåííèé îáñÿã âèïóñêó êîæíîãî âèäó<br />

âçóòòÿ.<br />

Ð î ç â ’ ÿ ç à í í ÿ. Íåõàé ùîäåííî ôàáðèêà âèïóñêຠõ 1<br />

ïàð äèòÿ÷îãî, õ 2 ïàð æ³íî÷îãî ³ õ 3 ïàð ÷îëîâ³÷îãî âçóòòÿ.<br />

Öåé ôàêò çàïèøåìî ó âèãëÿä³ âåêòîðà-ñòîâïöÿ:<br />

x<br />

æ ö x1<br />

= x<br />

2<br />

.<br />

ç çèx<br />

÷<br />

3 ø÷<br />

Òîä³, ó â³äïîâ³äíîñò³ äî çàòðàò ñèðîâèíè êîæíîãî âèäó<br />

áóäåìî ìàòè ìàòðè÷íå ð³âíÿííÿ Ax = b àáî ñèñòåìó<br />

ì x1+ 2x2 + 3x3<br />

=<br />

1300,<br />

ï<br />

íx1 + 3x2 + 4x3<br />

= 1700,<br />

ï ïî x1+ 2x2 + 5x3<br />

= 1700.<br />

Ðîçâ’ÿçîê ö³º¿ ñèñòåìè áóäåìî øóêàòè çà ïðàâèëîì<br />

Êðàìåðà.<br />

1 2 3 1 2 3 1300 2 3 13 2 3<br />

D= 1 3 4 = 0 1 1 = 2, D<br />

1<br />

= 1700 3 4 = 100× 17 3 4 =<br />

1 2 5 0 0 2 1700 2 5 17 2 5<br />

13 2 3 13 1 3<br />

5 1<br />

æ 1ö 5 1<br />

= ×- - = × 2 2 ç - × × × =- × - =<br />

çè 2÷<br />

ø<br />

2 1<br />

4 0 2<br />

201<br />

1+<br />

2<br />

100 0 100 2 2 5 0 1 200 ( 1) 600<br />

1 1300 3 1 1300 3 1 2 1300<br />

D = 1 1700 4 = 0 400 1 = 400, D = 1 3 1700 = 400.<br />

2 3<br />

1 1700 5 0 400 2 1 2 1700<br />

Çàñòîñóºìî òåïåð ôîðìóëè (3.3.2):<br />

D<br />

D<br />

D<br />

x = = x = = x = =<br />

D D D<br />

1 2<br />

3<br />

1<br />

300,<br />

2<br />

200,<br />

3<br />

200.<br />

Îòæå, çàäà÷ó ðîçâ’ÿçàíî ³ ìè ìîæåìî ñêàçàòè, ùî ôàáðèêà<br />

ùîäåííî âèïóñêຠ300 ïàð äèòÿ÷îãî ³ ïî 200 ïàð æ³íî-<br />

÷îãî òà ÷îëîâ³÷îãî âçóòòÿ.<br />

×èòà÷åâ³ ïðîïîíóºìî ðîç³áðàòèñÿ ç ïðèéîìàìè îá÷èñëåííÿ<br />

âèçíà÷íèê³â, à òàêîæ ðîçâ’ÿçàòè öþ çàäà÷ó ³íøèìè ìåòîäàìè.<br />

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