Minimum Average Cost
The cost of producing x units of a product is modeled by
C = 100 + 25x - 120 ln x, x ≥ 1.
(a) Find the average cost function Ć.
(b) Find the minimum average cost analytically. Use a graphing utility to confirm your result.

Respuesta :

Answer:

a)[tex]\bar{C}(x)=\dfrac{100}{x}+25-120\dfrac{lnx}{x}[/tex]

b)[tex]\bar{C}(x)=5.81[/tex]

Step-by-step explanation:

Given that

C = 100 + 25 x - 120 ln x   ,x ≥ 1.

The average cost function given as

[tex]\bar{C}(x)=\dfrac{C(x)}{x}[/tex]

[tex]\bar{C}(x)=\dfrac{100 + 25 x - 120 \ln x}{x}[/tex]

[tex]\bar{C}(x)=\dfrac{100}{x}+25-120\dfrac{lnx{x}[/tex]

Therefore

[tex]\bar{C}(x)=\dfrac{100}{x}+25-120\dfrac{lnx}{x}[/tex]

To find average minimum cost

[tex]\bar{C}(x)=\dfrac{100}{x}+25-120\dfrac{lnx}{x} [/tex]

[tex]\dfrac{d\bar{C}(x)}{dx} = -\dfrac{100}{x^2} +0-120\times \dfrac{1-lnx}{x^2}[/tex]

[tex]0 = -\dfrac{100}{x^2} +0- 120\times \dfrac{1-lnx}{x^2}[/tex]

100 + 120 (1-lnx) = 0

[tex]lnx=\dfrac{220}{120}[/tex]

ln x =1.833

[tex]x=e^{1.833}[/tex]

x=6.25

[tex]\bar{C}(x)=\dfrac{100}{6.25}+25-120\dfrac{ln6.25}{6.25}[/tex]

[tex]\bar{C}(x)=5.81[/tex]