Where is the graph of [tex]f(x) = 4[x - 3] + 2[/tex] discontinuous?

A. all real numbers
B. all integers
C. only at multiples of 3
D. only at multiples of 4



Answer :

To analyze the discontinuities of the function [tex]\( f(x) = 4\lfloor x - 3 \rfloor + 2 \)[/tex], we need to understand the behavior of the floor function, [tex]\(\lfloor x - 3 \rfloor\)[/tex].

The floor function, [tex]\(\lfloor y \rfloor\)[/tex], returns the greatest integer less than or equal to [tex]\( y \)[/tex]. Hence, [tex]\(\lfloor x - 3 \rfloor\)[/tex] is the greatest integer less than or equal to [tex]\( x - 3 \)[/tex].

The floor function, [tex]\(\lfloor x - 3 \rfloor\)[/tex], is discontinuous at all points where [tex]\( x - 3 \)[/tex] is an integer because at these points, the value of [tex]\( \lfloor x - 3 \rfloor \)[/tex] jumps from one integer to another.

For [tex]\( \lfloor x - 3 \rfloor \)[/tex] to be an integer, [tex]\( x - 3 \)[/tex] must be an integer. Therefore, [tex]\( x \)[/tex] itself must be an integer because adding 3 to any integer is another integer.

Thus, the function [tex]\( f(x) = 4\lfloor x - 3 \rfloor + 2 \)[/tex] is discontinuous at all integer values of [tex]\( x \)[/tex].

Therefore, the graph of [tex]\( f(x) = 4\lfloor x - 3 \rfloor + 2 \)[/tex] is discontinuous at:

[tex]\[ \boxed{\text{all integers}} \][/tex]