Questions: For f(x)=x^3+8, find each of the following.
a. f(-1)
b. f^(-1)(7).
c. (f ∘ f^(-1))(476)
a. f(-1)=
b. f^(-1)(7)=
c. (f ∘ f^(-1))(476)=
Transcript text: For $f(x)=x^{3}+8$, find each of the following.
a. $f(-1)$
b. $f^{-1}(7)$.
c. $\left(f \circ f^{-1}\right)(476)$
a. $f(-1)=$ $\square$
b. $f^{-1}(7)=$ $\square$
c. $\left(f \circ f^{-1}\right)(476)=$ $\square$
Solution
Solution Steps
To solve the given problems, we need to evaluate the function \( f(x) = x^3 + 8 \) and its inverse at specific points.
a. To find \( f(-1) \), substitute \( x = -1 \) into the function \( f(x) \).
b. To find \( f^{-1}(7) \), solve the equation \( 7 = x^3 + 8 \) for \( x \).
c. To find \( (f \circ f^{-1})(476) \), use the property that \( (f \circ f^{-1})(x) = x \).
Step 1: Evaluate \( f(-1) \)
To find \( f(-1) \), substitute \( x = -1 \) into the function \( f(x) = x^3 + 8 \):
\[
f(-1) = (-1)^3 + 8 = -1 + 8 = 7
\]
Step 2: Solve for \( f^{-1}(7) \)
To find \( f^{-1}(7) \), solve the equation \( 7 = x^3 + 8 \) for \( x \):
\[
7 = x^3 + 8 \implies x^3 = -1 \implies x = -1
\]
Step 3: Evaluate \( (f \circ f^{-1})(476) \)
By the property of inverse functions, \( (f \circ f^{-1})(x) = x \):
\[
(f \circ f^{-1})(476) = 476
\]