After t hours there are​ P(t) cells present in a​ culture, where ​P(t)equals2000e Superscript 0.3 t. ​(a) How many cells were present​ initially? ​(b) Give a differential equation satisfied by​ P(t). ​(c) When will the population​ double? ​(d) When will 8 comma 000 cells be​ present?

Respuesta :

Answer:

(a)2000 of cells were present initially.

(b)The differential equation of the given exponential model is

[tex]\frac{dP}{dt}=0.3P[/tex]

(c)The population will be double after 2.31 hours.

(d)The number of cell will be 8,000 after 4.62 hours.

Step-by-step explanation:

Given that,

[tex]P(t)= 2000e^{0.3 t}[/tex]

where P(t) is number of cell and t is time in hours.

(a)

Initial time means t=0.

Putting t=0 i the given expression

[tex]P(0)= 2000e^{0.3 \times 0}[/tex]

[tex]\Rightarrow P(0)= 2000[/tex]

2000 of cells were present initially.

(b)

The differential equation of population growth is

[tex]\frac{dP}{dt}=kP[/tex]

The solution of the above equation is

[tex]P(t)=Ce^{kt}[/tex]

Comparing the given exponential model to the above solution

So, k= 0.3 and C=2000

The differential equation of the given exponential model is

[tex]\frac{dP}{dt}=0.3P[/tex]

(c)

If the population double then P(t) = 2× P(0) =2×2000

[tex]P(t)= 2000e^{0.3 t}[/tex]

[tex]\Rightarrow 2\times 2000=2000e^{0.3t}[/tex]

[tex]\Rightarrow e^{0.3t}=2[/tex]

Taking ln both sides

[tex]\Rightarrow ln (e^{0.3t})=ln2[/tex]

[tex]\Rightarrow {0.3t=ln2[/tex]

[tex]\Rightarrow t=\frac{ln2}{0.3}[/tex]

[tex]\Rightarrow t=2.31[/tex] h

The population will be double after 2.31 hours.

(d)

Now P(t)=8,000

[tex]P(t)= 2000e^{0.3 t}[/tex]

[tex]\Rightarrow 8,000= 2000e^{0.3 t}[/tex]

[tex]\Rightarrow e^{0.3 t}=\frac{8,000}{2,000}[/tex]

[tex]\Rightarrow e^{0.3 t}=4[/tex]

Taking ln function both sides

[tex]\Rightarrow ln(e^{0.3 t})=ln 4[/tex]

[tex]\Rightarrow t=\frac{ln 4}{0.3}[/tex]

[tex]\Rightarrow t=4.62[/tex] h

The number of cell will be 8,000 after 4.62 hours.