Applications of Differentiation flashcards

36 practice cards drawn from the Applications of Differentiation lessons. Tap a card to turn it over. Every answer is checked against the lesson it came from.

Read the Applications of Differentiation lessons in full →

A tangent has gradient 4. What is the gradient of the normal?

−1/4

from “Tangents and Normals to Curves”

For y = x² at x = 4, the tangent line is

y = 8x − 16

from “Tangents and Normals to Curves”

The linearization of f at a is

f(a) + f'(a)(x − a)

from “The Tangent-Line Approximation”

f(2) = 5 and f'(2) = 3. Estimate f(2.1).

5.3

from “The Tangent-Line Approximation”

f(x) = x² on [0, 4]. The value of c the theorem promises is

2

from “The Mean Value Theorem”

The mean value theorem needs f differentiable

on the open interval

from “The Mean Value Theorem”

f'(x) = 0.2 at a point. Is f increasing there?

yes

from “Increasing and Decreasing Functions”

f'(x) = −3 at a point. Is f increasing there?

no

from “Increasing and Decreasing Functions”

y = x² − 4x. Where is the gradient zero?

x = 2

from “Finding Stationary Points”

y = x² − 6x. Where is the gradient zero?

x = 3

from “Finding Stationary Points”

f'(2) = 0. Is x = 2 a critical point?

yes

from “Critical Points and Local Extrema”

f has a cusp at x = 1, so f'(1) does not exist. Is x = 1 a critical point?

yes

from “Critical Points and Local Extrema”

At a flat point f'′ = −4. Peak or trough?

peak

from “The Second Derivative Test”

At a flat point f'′ = 6. Peak or trough?

trough

from “The Second Derivative Test”

f' goes +, 0, − across a flat point. Peak or trough?

peak

from “The First Derivative Test”

f'′ = 0 at a flat point. What settles peak or trough?

the sign of f' either side

from “The First Derivative Test”

On [0, 3], f(0) = 3, f(2) = −1 at the one critical point, f(3) = 0. The minimum is

−1

from “Absolute Extrema on a Closed Interval”

The extreme value theorem needs the interval to be

closed

from “Absolute Extrema on a Closed Interval”

f'′ changes from − to + at a point. What is that point?

a point of inflection

from “Points of Inflection”

At a point of inflection, which quantity changes sign?

f'′

from “Points of Inflection”

To find where a curve crosses the x-axis, set

y = 0

from “Curve Sketching with Derivatives”

To tell a peak from a trough, look at

f'′

from “Curve Sketching with Derivatives”

A rectangle has perimeter 24. What side length gives the biggest area?

6

from “Optimization Problems”

A rectangle has perimeter 16. What side length gives the biggest area?

4

from “Optimization Problems”

s = 2t². What is the velocity?

4t

from “Motion in a Straight Line”

s = 4t². What is the velocity?

8t

from “Motion in a Straight Line”

A = r², so dA/dr = 2r. At r = 5, r grows 3 per second. dA/dt = ?

30

from “Related Rates”

The balloon link gives dV/dr = 6 while dr/dt = 3. What is dV/dt?

18

from “Related Rates”

x = t, y = t². Eliminate t.

y = x²

from “Parametric Equations”

x = t², y = 2t. Where is the point at t = 2?

(4, 4)

from “Parametric Equations”

x = t², y = 2t. What is dy/dx?

1/t

from “Parametric Differentiation”

For a parametric curve, dy/dx equals

(dy/dt) / (dx/dt)

from “Parametric Differentiation”

Why does every term of have coefficient 1/n!?

every derivative of at 0 equals 1

from “Maclaurin Series”

The first two terms of the Maclaurin series of sin x are

x − x³/6

from “Maclaurin Series”

(eˣ − 1) / x at 0 goes to

1

from “L'Hôpital's Rule”

By L'Hôpital's rule, sin x / x at 0 goes to

1

from “L'Hôpital's Rule”

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