Questions: Suppose that the function f is defined, for all real numbers, as follows.
f(x) =
1/2 x^2 - 5 if x ≠ -2
-2 if x = -2
Find f(-5), f(-2), and f(3).
Transcript text: Suppose that the function $f$ is defined, for all real numbers, as follows.
\[
f(x)=\left\{\begin{array}{ll}
\frac{1}{2} x^{2}-5 & \text { if } x \neq-2 \\
-2 & \text { if } x=-2
\end{array}\right.
\]
Find $f(-5), f(-2)$, and $f(3)$
Solution
Solution Steps
To find the values of the function f(x) at specific points, we need to evaluate the function based on the given piecewise definition. For x=−2, we use the expression 21x2−5. For x=−2, we use the value −2.
Step 1: Evaluate f(−5)
For x=−5, since x=−2, we use the expression f(x)=21x2−5:
f(−5)=21(−5)2−5=21⋅25−5=12.5−5=7.5
Step 2: Evaluate f(−2)
For x=−2, we use the value given directly in the piecewise function:
f(−2)=−2
Step 3: Evaluate f(3)
For x=3, since x=−2, we use the expression f(x)=21x2−5:
f(3)=21(3)2−5=21⋅9−5=4.5−5=−0.5