A typical cup of coffee contains about 100 mg of caffeine and every hour approximately 16% ofthe amount of caffeine inthe body is metabolized and eliminated.a)Let C represent the amount of caffeine in the body in mg and f represent the number of hours since a cup of coffee was consumed. Write C as a function of r.
b) How much caf[eine is in the body after 5 hours?

Respuesta :

Answer:

a) [tex]\frac{dC}{dt} = rC[/tex]

And for this case we can rewrite the model like this:

[tex]\frac{dC}{C} = r dt[/tex]

If we integrate both sides we got:

[tex] ln C = rt + k[/tex]

If we use exponentials for both sides we got:

[tex] C = e^{rt} e^k = C_o e^{rt}[/tex]

For this case [tex] C_o = 100 mg[/tex] and r = -0.16

So then our model would be given by:

[tex] C(t) = 100 e^{-0.16 t}[/tex]

Where t represent the number of hours

b) [tex] C(5) = 100 e^{-0.16*5}= 44.9329[/tex]

Step-by-step explanation:

Part a

For this case we can assume the proportional model given by:

[tex]\frac{dC}{dt} = rC[/tex]

And for this case we can rewrite the model like this:

[tex]\frac{dC}{C} = r dt[/tex]

If we integrate both sides we got:

[tex] ln C = rt + k[/tex]

If we use exponentials for both sides we got:

[tex] C = e^{rt} e^k = C_o e^{rt}[/tex]

For this case [tex] C_o = 100 mg[/tex] and r = -0.16

So then our model would be given by:

[tex] C(t) = 100 e^{-0.16 t}[/tex]

Where t represent the number of hours

Part b

For this case we can replace the value t=5 into the model and we got:

[tex] C(5) = 100 e^{-0.16*5}= 44.9329[/tex]