Question 5 of 5

Jamaal bounces on a trampoline. His height, as a function of time, is modeled by [tex]$y=-16x^2 + 20x + 4$[/tex].

Which statement best describes the function?

A. The function is linear at some points and nonlinear at other points.
B. Not enough information is given to decide.
C. The function is linear.
D. The function is nonlinear.



Answer :

To analyze Jamaal's height over time and determine the nature of the function [tex]\( y = -16x^2 + 20x + 4 \)[/tex], let's carefully examine the mathematical form of the equation.

### Step-by-Step Solution:

1. Identify the Function Type:
- The given height function is [tex]\( y = -16x^2 + 20x + 4 \)[/tex].
- This is a quadratic function, characterized by the presence of the [tex]\( x^2 \)[/tex] term.

2. Quadratic Functions:
- A quadratic function is any function that can be written in the form [tex]\( y = ax^2 + bx + c \)[/tex], where [tex]\( a \)[/tex], [tex]\( b \)[/tex], and [tex]\( c \)[/tex] are constants, and [tex]\( a \neq 0 \)[/tex].
- In this particular function [tex]\( y = -16x^2 + 20x + 4 \)[/tex], the coefficient [tex]\( a \)[/tex] is [tex]\(-16\)[/tex], [tex]\( b \)[/tex] is 20, and [tex]\( c \)[/tex] is 4.

3. Characteristics of Quadratic Functions:
- Quadratic functions are non-linear because they form a parabolic shape when graphed. This is due to the [tex]\( x^2 \)[/tex] term, which causes the rate of change to vary.
- Unlike linear functions (which can be written in the form [tex]\( y = mx + b \)[/tex] and have a constant rate of change), quadratic functions do not have a constant rate of change.

4. Conclusion:
- Since [tex]\( y = -16x^2 + 20x + 4 \)[/tex] fits the standard form of a quadratic function, and quadratic functions are always nonlinear, we can conclude that this function is nonlinear.

Thus, the best description of the function is:

D. The function is nonlinear.