Answer:
Given:
A set of functions,
A. y = -(x-4)^2
B. y=3(x- 4)^2
C. y = [x] + 4
D. y = -5x + 4.
To Find:
The function whose range is (-infinity, 4].
Solution:
1. The function y = -(x-4)^2 has a minimum value of 0 and it is an increasing function. Hence the maximum value tends towards infinite. Hence the range is [0, infinite).
2. The function y = 3(x-4)^2 has a minimum value of 0 and it is an increasing function. Hence the maximum value tends towards infinite. Hence the range is [0, infinite).
3. y = [x] + 4 (where [x] = greatest integer function). This function is an increasing function with a minimum value towards negative infinity and the maximum value tends towards the positive side of infinity.
=> Range of y = [x] + 4 is (-infinite, infinite).
4. y = -5x+4 is a continuous increasing function without any exceptions.
=> Range of y = -5x+4 is (-infinite,infinite)
Therefore, none of the functions has their range from (-infinity,4].
Explanation: