Suppose that a population of bacteria triples every hour and starts with 700 bacteria. (a) Find an expression for the number n of bacteria after t hours.
(b) Estimate the rate of growth of the bacteria population after 1.5 hours.

(a) An expression for the number n of bacteria after t hours is n(t)=700*

(b) The rate of growth of the bacteria population after 1.5 hours is 3,996 number of bacteria per hour.

Step-by-step explanation:

An exponential function is one in which the independent variable x appears in the exponent and has a constant a as its base. Its expression is:

f(x)=aˣ

being a real positive.

When 0 <a <1, then the exponential function is a decreasing function and when a> 1, it is an increasing function.

An exponential function allows us to refer to phenomena that grow faster and faster, such as population growth.

In that case, the formula used to model the growth of a population is given by:

P(t)=P0*

where the function P (t) grows exponentially and represents the quantity of the population at time t; a represents the constant of growth or decrease and P0 represents the initial population at time zero.

In this case:

Replacing, you get:

P(t)=700*

An expression for the number n of bacteria after t hours is n(t)=700*

The derivative of this function P (t) is:

n'(t)=700*ln(3)*

and reflects the growth rate of the bacteria population.

So, the rate of growth of the bacteria population after 1.5 hours is:

n(1.5)=700*ln(3)*

Solving, you get:

n(1.5)≅ 3,996

The rate of growth of the bacteria population after 1.5 hours is 3,996 number of bacteria per hour.