Differential Equations Question 282

Question: The marginal cost of manufacturing a certain item is given by $ c’(x)=\frac{dc}{dx}=2+0.15x $ . The total cost function c (x), is

Options:

A) $ 0.075x^{2}+2x+100 $

B) $ 0.15x^{2}+3x+30 $

C) $ x^{2}+100.075x+100 $

D) None of these It is given that c (0) = 100

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Answer:

Correct Answer: A

Solution:

[a] [Note derivative of a function is sometimes called as the marginal value, especially in economics] Given $ \frac{dc}{dx}=2+0.15x $ Integrating we get $ c(x)=2x+0.15\frac{x^{2}}{2}+D $ when $ x=0,c(x)=100\Rightarrow D=100 $
$ \therefore $ the required equation is $ c(x)=0.075x^{2}+2x+100 $