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Òàêèì ÷èíîì, âàðò³ñòü ìàòåð³àë³â ³ ðîáî÷î¿ ñèëè äëÿ<br />

ïîáóäîâè øêîëè ñòàíîâèòü 4090 ãðí., äëÿ ïîáóäîâè äèòÿ÷îãî<br />

ñàäêà — 2800 ãðí., äëÿ ïîáóäîâè æèòëîâîãî áóäèíêó<br />

— 3210 ãðí.<br />

3. Ùîá â³äïîâ³ñòè íà òðåòº ïèòàííÿ, ñêëàäåìî äîáóòîê<br />

ìàòðèöü Â, À ³ Ð.  ðåçóëüòàò³ îòðèìàºìî, ùî ÂÀÐ = 55160.<br />

Îòæå, âàðò³ñòü óñ³õ ñïîðóä ñòàíîâèòü 55160 ãðí. (ïåâíà<br />

ð³÷, óìîâíî).<br />

×èòà÷åâ³ íàïîëåãëèâî ðåêîìåíäóºìî: 1) ïåðåâ³ðèòè âñ³<br />

ïðîì³æí³ âèêëàäêè; 2) ïîÿñíèòè, ÷îìó äîáóòîê ÑÀ íå ìàº<br />

ñìèñëó; 3) ïîêàçàòè âëàñòèâ³ñòü àñîö³àòèâíîñò³ ìàòðèöü Â,<br />

À ³ Ð.<br />

Íà çàê³í÷åííÿ â³äì³òèìî îñíîâí³ âëàñòèâîñò³ ìíîæåííÿ<br />

ìàòðèöü.<br />

1. À⋅0 =0.<br />

2. À⋅Å = E⋅À=A (A — êâàäðàòíà ìàòðèöÿ).<br />

3. Ó çàãàëüíîìó âèïàäêó À⋅Â ≠ Â⋅À (À⋅Â ³ Â⋅À ìàþòü<br />

ñåíñ). ßêùî À⋅Â = Â⋅À, òî ìàòðèö³ íàçèâàþòüñÿ ïåðåñòàâíèìè<br />

(êîìóòàòèâíèìè).<br />

4. Íåõàé À, Â, Ñ — ìàòðèö³, ÿê³ ìîæíà äîäàâàòè ³ ïåðåìíîæóâàòè,<br />

³ α — ÷èñëî. Òîä³ ìàþòü ì³ñöå ð³âíîñò³<br />

α⋅(À⋅Â) =(α⋅À)⋅Â = À⋅(α⋅Â), À⋅Â⋅C =(À⋅Â)⋅C = À⋅(Â⋅C),<br />

À⋅(Â + C) =À⋅Â + À⋅C.<br />

5. (À⋅Â) Ò = Â Ò ⋅À Ò .<br />

Äîâåäåìî âëàñòèâ³ñòü 2, ïðè÷îìó íå îáìåæóþ÷è çàãàëüí³ñòü<br />

ïðè n =2.<br />

Íåõàé<br />

Òîä³<br />

A<br />

⎛a<br />

a ⎞ ⎛10⎞<br />

⎜ ⎟ ⎜ ⎟.<br />

⎝ ⎠ ⎝01⎠<br />

11 12<br />

= , E =<br />

a21 a22<br />

⎛a ⋅ 1+ a ⋅0 a ⋅ 0+ a ⋅1⎞ ⎛a a ⎞<br />

A⋅ E = =<br />

11 12 11 12 11 12<br />

⎜ ⎟ ⎜ ⎟<br />

⎝a21 ⋅ 1+ a22 ⋅0 a21 ⋅ 0+ a22 ⋅1⎠ ⎝a21 a22<br />

⎠ ,<br />

⎛1⋅ a + 0⋅a 0⋅ a + 1⋅a ⎞ ⎛a a ⎞<br />

E⋅ A= =<br />

11 12 11 12 11 12<br />

⎜ ⎟ ⎜ ⎟<br />

⎝1⋅ a21 + 0⋅a22 0⋅ a21 + 1⋅a22 ⎠ ⎝a21 a22<br />

⎠ ,<br />

çâ³äêè âèïëèâàº, ùî À⋅Å = E⋅À = A. Îòæå, âëàñòèâ³ñòü 2 ïðè<br />

n = 2 äîâåäåíî.<br />

²íø³ âëàñòèâîñò³ ïðè n = 2 ðåêîìåíäóºìî ÷èòà÷åâ³ äîâåñòè<br />

ñàìîñò³éíî.<br />

2.3. ÂÈÇÍÀ×ÍÈÊ, ̲ÍÎÐÈ É ÀËÃÅÁÐÀ¯×Ͳ<br />

ÄÎÏÎÂÍÅÍÍß<br />

2.3.1. Îçíà÷åííÿ<br />

Ðîçãëÿíåìî êâàäðàòíó ìàòðèöþ<br />

A<br />

⎛a a ... a<br />

⎜<br />

⎜<br />

a a ... a<br />

... ... ... ...<br />

⎜<br />

⎝a a ... a<br />

11 12 1n<br />

21 22 2n<br />

= ⎜ ⎟<br />

n1 n2<br />

nn<br />

⎞<br />

⎟<br />

⎟<br />

. (2.3.1)<br />

⎟<br />

⎠<br />

¯é ìîæíà ïîñòàâèòè ó â³äïîâ³äí³ñòü âèçíà÷åíå ÷èñëî, ÿêå<br />

íàçèâàºòüñÿ äåòåðì³íàíòîì, àáî âèçíà÷íèêîì ìàòðèö³.<br />

Ïîçíà÷àºòüñÿ âîíî ñèìâîëàìè<br />

a11 a12 ... a1n<br />

=∆<br />

a a ... a<br />

=<br />

... ... ... ...<br />

=<br />

a a ... a<br />

21 22 2n<br />

det A<br />

A<br />

A .<br />

n1 n2<br />

nn<br />

(2.3.2)<br />

Ïîíÿòòÿ âèçíà÷íèêà ââîäèòüñÿ ò³ëüêè äëÿ êâàäðàòíèõ<br />

ìàòðèöü. Ââîäèòüñÿ òàêîæ ïîíÿòòÿ ïîðÿäêó âèçíà÷íèêà,<br />

ÿêèé äîð³âíþº ïîðÿäêó ìàòðèö³.<br />

̳íîðîì äåÿêîãî åëåìåíòà êâàäðàòíî¿ ìàòðèö³ íàçèâà-<br />

ºòüñÿ âèçíà÷íèê íîâî¿ ìàòðèö³, ÿêó îòðèìóºìî ³ç äàíî¿ ìàòðèö³<br />

âèêðåñëþâàííÿì ðÿäêà ³ ñòîâïöÿ, ùî ïåðåòèíàþòüñÿ íà<br />

öüîìó åëåìåíò³, íàïðèêëàä ì³íîð a ij -ãî åëåìåíòà ìàòðèö³ À ïîçíà÷àºòüñÿ<br />

òàê:<br />

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