Unit 3: Composite & Implicit Differentiation
Calculus AB · Unit 3 · Paper 3

Composite & Implicit Differentiation unit test

A test on this unit alone, marked as a percentage and a letter grade — for the test your class is actually sitting, rather than for May. Answer everything, then submit once: seeing the answer to question 3 before attempting question 4 makes the final percentage meaningless.

Each paper is built from this unit’s 38 terms and is the same for everyone, so a teacher can assign “Unit 3, Paper 3” and every student sits the identical test. Multiple choice is marked objectively; the written sections you mark yourself against the model answer and rubric.
Suggested time 36 min 33 points0/17 attempted
1

Related rates as implicit differentiation

2

Vertical and horizontal tangents implicitly

3

The xy term needs the product rule

4

The lost inner factor

5

Derivative of a variable base with a variable exponent

6

Why dy/dx involves y

7

Sign of an implicit second derivative

8

Derivative of a variable base and exponent

9

Vertical tangent from an implicit derivative

10

Higher-order derivatives of sine

11

Where to evaluate an inverse derivative

12

Circle slope formula

Short answer 1. Define or explain: Implicit differentiation

3 pts

Short answer 2. Define or explain: Collect and factor

3 pts

Short answer 3. Define or explain: Derivative of an inverse function

3 pts

Short answer 4. Define or explain: Implicit second derivative sign

3 pts

Free response

9 pts

NO CALCULATOR. Consider the curve defined by the equation x² + 2xy + 4y² = 12.

A. Show that dy/dx = −(x + y)/(x + 4y).

B. Find the equation of the line tangent to the curve at the point (2, 1).

C. Find the coordinates of a point on the curve at which the tangent line is horizontal, or explain why no such point exists.

D. Determine whether the curve has a vertical tangent line at any point where x = −4y, and justify your answer.