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:

\[ T(t) = -0.019t^2 + 0.4712t + 98.3 \]

Use your calculator to graph the function and answer the following questions. Round all answers to 1 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] degrees Fahrenheit

Answer :

To solve the problem of finding when the patient's temperature reaches its maximum value and what that maximum temperature is, we need to analyze the given temperature function:

[tex]\[ T(t) = -0.019t^2 + 0.4712t + 98.3 \][/tex]

This function is a quadratic equation in the form of [tex]\( T(t) = at^2 + bt + c \)[/tex], where [tex]\( a = -0.019 \)[/tex], [tex]\( b = 0.4712 \)[/tex], and [tex]\( c = 98.3 \)[/tex].

### Finding When the Temperature Reaches Its Maximum

Since the function is a downward-opening parabola (as indicated by the negative coefficient of [tex]\( t^2 \)[/tex]), it will have a maximum point at its vertex. The formula to find the vertex [tex]\( t \)[/tex] for the maximum or minimum value of a quadratic equation [tex]\( ax^2 + bx + c \)[/tex] is:

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

Plugging the values of [tex]\( a \)[/tex] and [tex]\( b \)[/tex] into the formula:

[tex]\[ t = -\frac{0.4712}{2 \times -0.019} \][/tex]

When calculated, this results in:

[tex]\[ t = 12.4 \][/tex]

This tells us that the patient's temperature reaches its maximum value after 12.4 hours.

### Finding the Maximum Temperature

Next, we substitute [tex]\( t = 12.4 \)[/tex] back into the function to find the maximum temperature:

[tex]\[ T(12.4) = -0.019(12.4)^2 + 0.4712(12.4) + 98.3 \][/tex]

After performing the calculations, the maximum temperature is found to be:

[tex]\[ T = 101.2 \][/tex] degrees Fahrenheit

### Conclusion

Thus, the patient's temperature reaches its maximum value after 12.4 hours, and the maximum temperature during the illness is 101.2 degrees Fahrenheit.