Cogito
Calculus · Chapter 5 · Lesson 1
Rates of Change and Related Rates
The derivative as a speed.
10 problems · about 22 minutes · CHA-3.A, CHA-3.B
Figure — use these to answer the problems
- Point(2, 4)
- Slope of the tangent4
Warm-Up Review
From earlier lessons. Loosen up before the new work.
2 problemsFrom “The Chain Rule”
For (6x + 1)³, what is the inner derivative?
AnswerFrom “The Product and Quotient Rules”
y = x² (3x + 1), so y′ = 9x² + 2x. What is y′ at x = 2?
Answer
Warm Up
Straightforward practice. Get the method working first.
4 problemsA square with side 7 growing at 2 cm/s. Area rate?
AnswerWhat does a derivative measure in a real situation?
- How fast one quantity changes as another does.
- The total amount.
v(t) = 2t. Velocity at t = 9?
AnswerA square with side 6 growing at 2 cm/s. Area rate?
Answer
Build It Up
The same ideas with more to keep track of.
2 problemsA square with side 10 growing at 1 cm/s. Area rate?
AnswerWhat is the derivative of velocity?
- Acceleration.
- Position.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problemsThe Velocity
s(t) = t², so v(t) = 2t. What is the velocity at t = 6?
AnswerThe Square
A square with side 4 growing at 3 cm/s. How fast is the area growing?
Answercm² per second