Cogito
AP Calculus AB · Chapter 2 · Lesson 1
The Derivative as a Limit
Bringing the two points together.
11 problems · about 25 minutes · AP Calculus AB 2.1, 2.2
Figure — use these to answer the problems
- Point(2, 4)
- Second point(5, 25)
- Slope between them7
Warm Up
Straightforward practice. Get the method working first.
4 problemsf(x) = x². What is f'(7)?
Answerf(x) = x². What is f'(1)?
Answerf(x) = x². What is f'(0)?
Answerf(x) = 5x + 2. What is f'(9)?
Answer
Build It Up
The same ideas with more to keep track of.
3 problemsSet the two points together at x = 2 so the secant becomes the tangent, and the slope reads 4.
Set the model in the app, then write the values you used.
The difference quotient for f(x) = x² at a = 4 simplifies to 8 + h. What is the derivative?
Answerf(x) = x³. What is f'(2)? The derivative of x³ is 3x².
Answer
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
4 problemsIs the derivative an average rate or an instantaneous rate? 1 for average, 2 for instantaneous.
Answerf(x) = 7. What is f'(3)?
AnswerFrom the Definition
For f(x) = x², what is f'(5)?
AnswerReading the Tangent
The tangent to y = x² at x = 2 is shown. What is its slope?
The tangent at x = 2. - Point(2, 4)
- Slope of the tangent4
abcPoint of tangencyAnswer