College

A patient has an illness that typically lasts about 24 hours. The temperature, [tex]T[/tex], in degrees Fahrenheit, of the patient [tex]t[/tex] hours after the illness begins is given by:

[tex]T(t) = -0.024t^2 + 0.5136t + 97.9[/tex]

Use your calculator to graph the function and answer the following questions. Round all answers to one decimal place.

1. When does the patient's temperature reach its maximum value?
- Answer: After [tex]\square[/tex] hours

2. What is the patient's maximum temperature during the illness?
- Answer: [tex]\square[/tex] °F

Answer :

To solve this problem, we need to determine when the patient's temperature reaches its maximum value and what that maximum temperature is during the illness. The temperature function is given as:

[tex]\[ T(t) = -0.024t^2 + 0.5136t + 97.9 \][/tex]

This is a quadratic function of the form [tex]\( ax^2 + bx + c \)[/tex], and the graph of this function is a downward-opening parabola because the coefficient of [tex]\( t^2 \)[/tex], which is [tex]\(-0.024\)[/tex], is negative.

### Finding the Time of Maximum Temperature

The vertex of a parabola in the form [tex]\( y = ax^2 + bx + c \)[/tex] gives the maximum point when [tex]\( a < 0 \)[/tex]. The formula to find the time [tex]\( t \)[/tex] at which the maximum temperature occurs is:

[tex]\[ t = -\frac{b}{2a} \][/tex]

For our given function:
- [tex]\( a = -0.024 \)[/tex]
- [tex]\( b = 0.5136 \)[/tex]

Substitute these values into the vertex formula:

[tex]\[ t = -\frac{0.5136}{2 \times -0.024} \][/tex]

Solving this, we find:

[tex]\[ t = 10.7 \][/tex]

So, the patient's temperature reaches its maximum value 10.7 hours after the illness begins.

### Finding the Maximum Temperature

To find the maximum temperature, substitute [tex]\( t = 10.7 \)[/tex] back into the temperature function [tex]\( T(t) \)[/tex]:

[tex]\[ T(10.7) = -0.024 \times (10.7)^2 + 0.5136 \times 10.7 + 97.9 \][/tex]

Calculate this expression to find:

[tex]\[ T(10.7) = 100.6 \][/tex]

Therefore, the patient's maximum temperature during the illness is 100.6 degrees Fahrenheit.

In summary:
- The patient's temperature reaches its maximum 10.7 hours after the illness begins.
- The maximum temperature is 100.6°F.