Save
...
Unit 5: Analytical Applications of Differentiation
5.6 Determining Concavity and Points of Inflection
Using the second derivative to determine concavity:
Save
Share
Learn
Content
Leaderboard
Share
Learn
Cards (134)
What is concavity if the graph of a function bends upward?
Concave upward
Upward concavity occurs when the
slope
of the function is increasing.
True
Points of inflection occur where <img src="https://render.githubusercontent.com/render/svg?math=f''(x)"> is equal to zero or
undefined
What is the interpretation of the second derivative <img src="https://render.githubusercontent.com/render/svg?math=f''(x)">?
Rate of change of slope
A positive second derivative indicates
upward
concavity.
True
To find the second derivative, differentiate the first derivative
twice
If the second derivative of a function is negative, the function has downward
concavity
.
True
Match the condition with its concavity:
f
′
′
(
x
)
>
0
f''(x) > 0
f
′′
(
x
)
>
0
↔️ Concave upward
f
′
′
(
x
)
<
0
f''(x) < 0
f
′′
(
x
)
<
0
↔️ Concave downward
f
′
′
(
x
)
=
f''(x) =
f
′′
(
x
)
=
0
0
0
↔️ Potential point of inflection
For the function
f
(
x
)
=
f(x) =
f
(
x
)
=
x
3
−
6
x
2
+
x^{3} - 6x^{2} +
x
3
−
6
x
2
+
5
x
−
10
5x - 10
5
x
−
10
, what is
f
′
′
(
x
)
f''(x)
f
′′
(
x
)
?
6
x
−
12
6x - 12
6
x
−
12
For the function
f
(
x
)
=
f(x) =
f
(
x
)
=
x
3
−
6
x
2
+
x^{3} - 6x^{2} +
x
3
−
6
x
2
+
5
x
−
10
5x - 10
5
x
−
10
, when x < 2</latex>,
f
′
′
(
x
)
<
0
f''(x) < 0
f
′′
(
x
)
<
0
and the function is concave downward.
True
The first derivative test determines concavity based on the rate of change of
f'(x)
.
A function is concave upward if it curves like a
cup
.
The second derivative indicates the rate of change of the slope of
f
(
x
)
f(x)
f
(
x
)
.
If <img src="https://render.githubusercontent.com/render/svg?math=f''(x) > 0">, the function is concave
upward
If <img src="https://render.githubusercontent.com/render/svg?math=f''(x) > 0">, the function is concave
upward
If <img src="https://render.githubusercontent.com/render/svg?math=f''(x) < 0">, the function is concave
downward
If <img src="https://render.githubusercontent.com/render/svg?math=f'(x)"> is increasing, the function is concave
upward
If <img src="https://render.githubusercontent.com/render/svg?math=f''(x)"> changes sign around a point, it is a valid
point of inflection
.
True
x
=
x =
x
=
2
2
2
is a point of inflection
What condition must be met for a potential point of inflection to be valid?
The sign of
f
′
′
(
x
)
f''(x)
f
′′
(
x
)
must change
Steps to apply the second derivative test:
1️⃣ Find the second derivative
f
′
′
(
x
)
f''(x)
f
′′
(
x
)
2️⃣ Determine critical points by setting
f
′
′
(
x
)
=
f''(x) =
f
′′
(
x
)
=
0
0
0
or finding undefined values
3️⃣ Create intervals using critical points
4️⃣ Choose a test value from each interval
5️⃣ Evaluate
f
′
′
(
x
)
f''(x)
f
′′
(
x
)
for each test value
6️⃣ Determine concavity based on the sign of
f
′
′
(
x
)
f''(x)
f
′′
(
x
)
If
f
′
′
(
x
)
>
0
f''(x) > 0
f
′′
(
x
)
>
0
, the function is concave upward.
True
Match the concavity with its definition:
Upward ↔️ The function is curving upward
Downward ↔️ The function is curving downward
What does a negative second derivative imply about concavity?
Concave downward
What does the second derivative of a function indicate?
Rate of change of slope
If <img src="https://render.githubusercontent.com/render/svg?math=f''(x) < 0"/>, the function is
concave
downward.
True
What is the sign of the second derivative when a function is concave upward?
Positive
What does the second derivative <img src="https://render.githubusercontent.com/render/svg?math=f''(x)"> describe?
Rate of change of slope
When a function is curving upward, it is said to have
upward
concavity.
If the second derivative of a function is positive, what is its concavity?
Upward
Steps to find the second derivative of a function
1️⃣ Calculate the first derivative
2️⃣ Differentiate the first derivative
When
f
′
′
(
x
)
<
0
f''(x) < 0
f
′′
(
x
)
<
0
, the function is concave downward.
True
For the function
f
(
x
)
=
f(x) =
f
(
x
)
=
x
3
−
6
x
2
+
x^{3} - 6x^{2} +
x
3
−
6
x
2
+
5
x
−
10
5x - 10
5
x
−
10
, what is
f
′
(
x
)
f'(x)
f
′
(
x
)
?
3
x
2
−
12
x
+
3x^{2} - 12x +
3
x
2
−
12
x
+
5
5
5
What is the bending direction of a function when
f
′
′
(
x
)
<
0
f''(x) < 0
f
′′
(
x
)
<
0
?
Downward
When
f
′
′
(
x
)
<
0
f''(x) < 0
f
′′
(
x
)
<
0
, the function curves downward.
True
When
f
′
(
x
)
f'(x)
f
′
(
x
)
is decreasing, the second derivative is negative.
True
If
f
′
′
(
x
)
>
0
f''(x) > 0
f
′′
(
x
)
>
0
, the function is concave upward.
True
What does the second derivative of a function indicate?
Rate of change of slope
What does <img src="https://render.githubusercontent.com/render/svg?math=f''(x) = 0"> indicate about the function?
Potential point of inflection
What does <img src="https://render.githubusercontent.com/render/svg?math=f''(x) = 0"> indicate about the function?
Potential point of inflection
See all 134 cards