Chain Rule with Table-Defined Functions

Use the chain rule to evaluate derivatives of compositions f(g(x)) or related expressions where f and g are defined only through a table of values.

ap-calculus-ab 2007 Q3 View
The functions $f$ and $g$ are differentiable for all real numbers, and $g$ is strictly increasing. The table below gives values of the functions and their first derivatives at selected values of $x$.
$x$$f(x)$$f^{\prime}(x)$$g(x)$$g^{\prime}(x)$
16425
29231
310-442
4-1367

The function $h$ is given by $h(x) = f(g(x)) - 6$.
(a) Explain why there must be a value $r$ for $1 < r < 3$ such that $h(r) = -5$.
(b) Explain why there must be a value $c$ for $1 < c < 3$ such that $h^{\prime}(c) = -5$.
(c) Let $w$ be the function given by $w(x) = \int_{1}^{g(x)} f(t)\, dt$. Find the value of $w^{\prime}(3)$.
(d) If $g^{-1}$ is the inverse function of $g$, write an equation for the line tangent to the graph of $y = g^{-1}(x)$ at $x = 2$.
ap-calculus-ab 2016 Q6 View
The functions $f$ and $g$ have continuous second derivatives. The table below gives values of the functions and their derivatives at selected values of $x$.
$x$$f ( x )$$f ^ { \prime } ( x )$$g ( x )$$g ^ { \prime } ( x )$
1$-6$328
22$-2$$-3$0
38762
6453$-1$

(a) Let $k ( x ) = f ( g ( x ) )$. Write an equation for the line tangent to the graph of $k$ at $x = 3$.
(b) Let $h ( x ) = \frac { g ( x ) } { f ( x ) }$. Find $h ^ { \prime } ( 1 )$.
(c) Evaluate $\int _ { 1 } ^ { 3 } f ^ { \prime \prime } ( 2 x ) \, d x$.
ap-calculus-ab 2017 Q6 View
Let $f$ be the function defined by $f(x) = \cos(2x) + e^{\sin x}$.
Let $g$ be a differentiable function. The table below gives values of $g$ and its derivative $g'$ at selected values of $x$.
\multicolumn{1}{|c|}{$x$}$g(x)$$g'(x)$
-510-3
-45-1
-324
-231
-11-2
00-3

Let $h$ be the function whose graph, consisting of five line segments, is shown in the figure above.
(a) Find the slope of the line tangent to the graph of $f$ at $x = \pi$.
(b) Let $k$ be the function defined by $k(x) = h(f(x))$. Find $k'(\pi)$.
(c) Let $m$ be the function defined by $m(x) = g(-2x) \cdot h(x)$. Find $m'(2)$.
(d) Is there a number $c$ in the closed interval $[-5, -3]$ such that $g'(c) = -4$? Justify your answer.
ap-calculus-ab 2023 Q5 View
The functions $f$ and $g$ are twice differentiable. The table shown gives values of the functions and their first derivatives at selected values of $x$.
$x$0247
$f(x)$10745
$f'(x)$$\frac{3}{2}$$-8$36
$g(x)$12$-3$0
$g'(x)$5428

(a) Let $h$ be the function defined by $h(x) = f(g(x))$. Find $h'(7)$. Show the work that leads to your answer.
(b) Let $k$ be a differentiable function such that $k'(x) = (f(x))^{2} \cdot g(x)$. Is the graph of $k$ concave up or concave down at the point where $x = 4$? Give a reason for your answer.
(c) Let $m$ be the function defined by $m(x) = 5x^{3} + \int_{0}^{x} f'(t)\, dt$. Find $m(2)$. Show the work that leads to your answer.
(d) Is the function $m$ defined in part (c) increasing, decreasing, or neither at $x = 2$? Justify your answer.