Question

Write the equation of a piecewise function with a jump discontinuity at x =3. Then, determine which step of the 3-step test for continuity that the function
fails.

Answer 1

Answer:

Here's a possible example:

Step-by-step explanation:

$f(x) =\begin{cases} x & \quad x < 3\\x+3 & \quad x \geq 3\\\end{cases}$

Each piece is linear, so the pieces are continuous by themselves.

We need consider only the point at which the pieces meet (x = 3).

$\displaystyle \lim_{x \longrightarrow 3^{-}} f(x) = \lim_{x \longrightarrow 3^{-}} x = 3\\\\\displaystyle \lim_{x \longrightarrow 3^{+}} f(x) = \lim_{x \longrightarrow 3^{+}} x+3 = 6\\\\f(3) = x + 3 = 6\\\\\displaystyle \lim_{x \longrightarrow 3^{-}} f(x) \neq f(3)$

The left-hand limit does not equal ƒ(x), so there is a jump discontinuity at x =3.