Applied Mathematics for Business and Economics

(sharon) #1

Lecture Note Differentiation


h. yxx=− +20 4(^2 )( (^21) ) i. (^) () ()^32


1


21


5


fx= x−+x

j. fx()=− (^35) (x^3 − +2 4x ) k.


23


54


x
y
x


=


+


l. ()

3


3


fx
x

=


+


2 rkGRtaERbRbYlénGnuKmn_f(x)eFobeTAnwg xcMeBaHtémøxEdleKbBa¢ak; (Find the


rate of change of the given functionf(x)with respect to x for the prescribed
value of x. )

a.fx x x()=−+ =^3 35, 2x , b. fx( )= x xx+=5, 4


c.fx()=+ + =()x^2 2,()x x x 4 d.f(xx)=(^23 +− =352 , 1)( xx)

e. ()


21


,1


35


x
f xx
x


==


+


f. (^) ()


3


,0


24


fx x x
x

= +=



3 eKrMBwgTukfakñúgry³eBltqñaMKitBIeBlenHeTA cracrN_énsarBt’mankñúgRsukmYynwg


esμIeTAnwg Ct()=+ 100 t^2400 t+5, 000.


k> cUrTajrkenSammYyEdltag[GRtabMErbMrYléncracrN_sarBt’maneFobeTAnwg


eBlt.


x> etIcracrN_sarBt’mannwgERbRbYlkñúgGRtab:unμaneFobnwgeBlkñúgry³eBl5qñaM


BIeBlenH eTA? etIenAeBlenaHcracrN_sarBt’man ekIneLIg b¤Føak;cuH?


K> etIenAqñaMTI6 cracrN_sarBt’mannwgERbRbYlCak;EsþgkñúgTMhMb:unμan?
(It is estimated that t years from now, the circulation of a local newspaper will be

. a/. Derive an expression for the rate at which the
circulation will be changing with respect to time t years from now. b/. At what
rate will the circulation be changing with respect to time 5 years from now? Will
the circulation be increasing or decreasing at that time? c/. By how much will the
circulation actually change during the 6th year?)


Ct()=++ 100 t^2400 t5, 000

(a/.Ct′()=+ 200 t 400 ,b/.Increasing at the rate of 1,400 per year, c/. 1,500)

4 karsikSaGMBIRbsiT§PaBkargarevnRBwkenAkñúgeragcRkmYy)anbgðaj[eXIjfa CamFüm


kmμkrEdlmk dl;kEnøgeFVIkarenAem:ag8³00RBwk n


()

(^3261)
wgRbmUlviTüú)ancMnYn
f xxx=− + + 5 xkñúgry³eBl xem:ag bnÞab;.
k> TajrkkenSammYytag[GRtaénkarRbmUlviTüúrbs;kmμkr
bnÞab;BI)ancab;epþImkargarry³eBl xem:ag.
x> etIGRtaénkarRbmUlenAem:ag9³00esμInwgb:unμan?

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