Math Problem Statement

The temperature of a person during a certain illness is given by the following​ equation, where T is the temperature ​(degrees​F) at time​ t, in days. Find the relative extreme points and sketch a graph of the function. ​T(t)equalsnegative 0.3 t squared plus 2.4 t plus 98.5​, 0less than or equalstless than or equals8

Solution

To find the relative extreme points of the temperature function T(t)=0.3t2+2.4t+98.5T(t) = -0.3t^2 + 2.4t + 98.5 over the interval [0,8][0, 8], we first need to determine the critical points by taking the derivative and setting it to zero.

  1. Calculate the derivative: T(t)=0.6t+2.4T'(t) = -0.6t + 2.4

  2. Set the derivative equal to zero to find critical points: 0.6t+2.4=0-0.6t + 2.4 = 0 0.6t=2.40.6t = 2.4 t=4t = 4

  3. Evaluate T(t)T(t) at the critical point and endpoints:

    • At t=0t = 0: T(0)=0.3(0)2+2.4(0)+98.5=98.5T(0) = -0.3(0)^2 + 2.4(0) + 98.5 = 98.5
    • At t=4t = 4: T(4)=0.3(4)2+2.4(4)+98.5=0.3(16)+9.6+98.5=4.8+9.6+98.5=103.3T(4) = -0.3(4)^2 + 2.4(4) + 98.5 = -0.3(16) + 9.6 + 98.5 = -4.8 + 9.6 + 98.5 = 103.3
    • At t=8t = 8: T(8)=0.3(8)2+2.4(8)+98.5=0.3(64)+19.2+98.5=19.2+19.2+98.5=98.5T(8) = -0.3(8)^2 + 2.4(8) + 98.5 = -0.3(64) + 19.2 + 98.5 = -19.2 + 19.2 + 98.5 = 98.5
  4. Summarize the values:

    • T(0)=98.5T(0) = 98.5
    • T(4)=103.3T(4) = 103.3 (relative maximum)
    • T(8)=98.5T(8) = 98.5

The relative extreme point is at t=4t = 4 with a maximum temperature of 103.3103.3 °F. The function decreases before and after this point within the interval.

Graph Sketch

To sketch the graph, plot the points:

  • (0, 98.5)
  • (4, 103.3)
  • (8, 98.5)

The parabola opens downwards, with a vertex at (4,103.3)(4, 103.3).

Summary

  • Relative maximum at t=4t = 4 with T(4)=103.3T(4) = 103.3 °F.
  • The temperature decreases on either side of this point within the interval [0,8][0, 8].

Would you like more details or have any questions? Here are some related questions you might consider:

  1. What is the significance of finding relative extreme points in this context?
  2. How would the graph change if the coefficient of t2t^2 were positive?
  3. What does the negative coefficient of t2t^2 indicate about the temperature trend?
  4. Can you explain the role of derivatives in finding extreme points?
  5. How would you interpret the results if T(t)T(t) represented a different scenario, like a medication effect over time?

Tip: Always check the endpoints of your interval when looking for relative extrema!

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Math Problem Analysis

Mathematical Concepts

Calculus
Quadratic Functions
Graphing

Formulas

T(t) = -0.3t^2 + 2.4t + 98.5
T'(t) = -0.6t + 2.4

Theorems

Extreme Value Theorem

Suitable Grade Level

Grades 11-12