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Ô(t) =7⋅ 10 6 +3⋅ 10 6 e –0,1t .<br />

ρ<br />

6<br />

Î÷åâèäíî, ùî limΦ () t = I = 7⋅10<br />

. Öå îçíà÷àº, ùî äëÿ<br />

t →∞ µ<br />

ðîçãëÿíóòîãî âèïàäêó ³ç çðîñòàííÿì ÷àñó âåëè÷èíà Ô çíà-<br />

÷íî çìåíøóºòüñÿ. Íå äóæå âò³øíà êàðòèíà. Àëå ç³ ñòðóêòóðè<br />

ð³âíÿííÿ ìîæíà çðîáèòè òàêèé âèñíîâîê: äëÿ òîãî ùîá<br />

ôîíä ï³äïðèºìñòâà íå çìåíøóâàâñÿ, òðåáà çä³éñíþâàòè ñòðàòåã³þ<br />

òàê, ùîá ³íâåñòèö³ÿ áóëà çì³ííîþ ³ çàäîâîëüíÿëà<br />

óìîâó<br />

1<br />

≥ Φ .<br />

7<br />

() () t<br />

I t<br />

11.9.3. Ìîäåëü Ñîëîó<br />

Ñòàí åêîíîì³êè, ÿê ºäèíå ö³ëå, çàäàºòüñÿ ï’ÿòüìà çì³ííèìè<br />

ñòàíó: Q — ê³íöåâèé ïðîäóêò, L — òðóäîâ³ ðåñóðñè,<br />

K — âèðîáíè÷³ ôîíäè, ² — ³íâåñòèö³¿, Ñ — ðîçì³ð íåâèðîáíè÷îãî<br />

ñïîæèâàííÿ.  ë³òåðàòóð³ ç åêîíîì³êè, â ðàìêàõ<br />

ìîäåë³ Ñîëîó, ï’ÿòü çãàäàíèõ âèùå çì³ííèõ ïîâ’ÿçàí³ ì³æ<br />

ñîáîþ òàêèìè ñï³ââ³äíîøåííÿìè:<br />

( ) ( ) 0<br />

C = 1 −ρ Q, 0 ≤ρ< 1; Q = Q K, L ; L = L e νt ;<br />

dK<br />

Q K,<br />

K( o) K0<br />

dt =ρ −µ = . (11.9.12)<br />

Òóò âåëè÷èíà ρ íàçèâàºòüñÿ íîðìîþ íàêîïè÷åííÿ ³ õàðàêòåðèçóº<br />

äîëþ ê³íöåâîãî ïðîäóêòó, ÿêó âèêîðèñòîâóþòü<br />

íà ³íâåñòèö³¿; âåëè÷èíà µ º êîåô³ö³ºíò âèáóòòÿ ôîíä³â. Áóäåìî<br />

ïðè öüîìó ââàæàòè, ùî âèðîáíè÷à ôóíêö³ÿ Q = Q(K, L)<br />

º îäíîð³äíîþ ôóíêö³ºþ ïåðøîãî ïîðÿäêó, òîáòî<br />

Q(λK, λL) =λQ(K, L) (ïðèðîäíà óìîâà äëÿ âèðîáíè÷èõ ôóíêö³é<br />

â åêîíîì³ö³). Ââåäåìî ïîçíà÷åííÿ:<br />

Q K<br />

q = , k<br />

L<br />

= L<br />

. (11.9.13)<br />

Óâåäåí³ âåëè÷èíè â³äïîâ³äíî íàçèâàþòüñÿ ñåðåäíüîþ ïðîäóêòèâí³ñòþ<br />

ïðàö³ ³ ñåðåäíüîþ ôîíäîîçáðîºí³ñòþ.<br />

Âðàõîâóþ÷è ïîçíà÷åííÿ (11.8.13) ³ îäíîð³äí³ñòü ôóíêö³¿<br />

Q = Q(K, L), îòðèìàºìî<br />

( , )<br />

Q Q K L ⎛K<br />

⎞<br />

q = = = Q ,1 Q( k,1) q( k)<br />

L L<br />

⎜ = =<br />

L<br />

⎟<br />

.<br />

⎝ ⎠<br />

Äàë³, ïðîäèôåðåíöþºìî âåëè÷èíó k ïî çì³íí³é t.  ðåçóëüòàò³<br />

ìàòèìåìî:<br />

(<br />

K<br />

)<br />

dk d<br />

L K′ L − KL′ K′ L′<br />

= = = − K =<br />

2 2<br />

dt dt L L L<br />

ρQ −µ K K<br />

= −ν = ρq( k) − ( µ +ν ) k.<br />

L L<br />

dk<br />

=ρ − µ+ν k, (11.9.14)<br />

dt<br />

Îñòàòî÷íî: q( k) ( )<br />

k<br />

K<br />

0<br />

( 0) k<br />

=<br />

0<br />

=<br />

L<br />

. (11.9.15)<br />

0<br />

Çàóâàæèìî, ùî â ëàíöþæêó ïåðåòâîðåíü, ÿê³ ïðèâåëè íàñ<br />

äî äèôåðåíö³àëüíîãî ð³âíÿííÿ (11.9.4) ³ ïî÷àòêîâî¿ óìîâè<br />

(11.9.15), ìè ñêîðèñòàëèñÿ ñï³ââ³äíîøåííÿìè (11.9.13).<br />

Ïðèêëàä 11.9.3. Íåõàé ( )<br />

ρ= 10 −1 ,<br />

1 1<br />

, 10 9 2 2<br />

Q K L = ⋅ K L , k<br />

0<br />

= 5 ,<br />

1<br />

µ=ν= . Òðåáà çíàéòè ñåðåäíþ ôîíäîîçáðîºí³ñòü<br />

2<br />

ï³äïðèºìñòâà.<br />

гâíÿííÿ (11.9.14) ïðè çàäàíèõ óìîâàõ íàáóäå âèãëÿäó:<br />

dk<br />

k k<br />

dt + = ⋅<br />

1<br />

10 5 2<br />

448 449

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