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How to find local extrema using the Second Derivative Test?
- Find critical points. 2. Compute the second derivative. 3. Evaluate the second derivative at each critical point. 4. Determine if each point is a local max, min, or neither.
Steps to determine concavity of a function.
- Find the second derivative, . 2. Set and solve for x. 3. Create a sign chart for . 4. Determine intervals of concave up () and concave down ().
How to find inflection points?
- Find the second derivative, . 2. Set and solve for x. 3. Check if the concavity changes at each potential inflection point.
What to do if the Second Derivative Test is inconclusive?
Use the First Derivative Test or analyze the behavior of the function around the critical point.
How to use the second derivative to determine if is a local max?
Find , set to confirm c is a critical point. Then, find and evaluate . If , then is a local max.
How to use the second derivative to determine if is a local min?
Find , set to confirm c is a critical point. Then, find and evaluate . If , then is a local min.
How to find the global extremum given one critical point?
If the function is continuous and has only one critical point, and that point is a local extremum, then it's also the global extremum.
How to find critical points for on ?
- Find . 2. Set . 3. Solve for x, which gives .
Given and critical point , how to determine if it's a local max or min?
- Find . 2. Evaluate . 3. Since , it's a local max.
How to determine the nature of critical points when ?
- Set to find critical points, but there are none. 2. Check where is undefined, which is at . 3. Since is not defined at , there are no local extrema.
How does the graph of relate to the graph of ?
The graph of shows the concavity of . Positive means is concave up, negative means is concave down.
What does an inflection point look like on the graph of ?
It's a point where the graph changes concavity, from concave up to concave down or vice versa.
How can you identify local extrema on the graph of ?
Local maxima are peaks, and local minima are valleys. The tangent line at these points is horizontal (slope = 0).
If the graph of is always positive, what does this tell you about ?
is always concave up.
If the graph of is always negative, what does this tell you about ?
is always concave down.
How can you identify critical points from the graph of ?
Critical points occur where intersects the x-axis (i.e., ) or where is undefined.
What does the sign of tell you about the graph of ?
If , is increasing. If , is decreasing.
How to identify a local max on the graph of ?
The graph of crosses the x-axis from positive to negative.
How to identify a local min on the graph of ?
The graph of crosses the x-axis from negative to positive.
How to identify inflection points on the graph of ?
Inflection points occur where has a local max or min.
What is the formula for the second derivative?
How to determine critical points?
Solve or find where is undefined.
Second Derivative Test: Local Minimum
If and , then is a local minimum.
Second Derivative Test: Local Maximum
If and , then is a local maximum.
How to find the second derivative of ?
,
What is the second derivative of ?
,
What is the second derivative of ?
,
What is the formula to check for concavity?
Check the sign of .
What is the formula to find inflection points?
Solve or find where is undefined.
What is the formula for the second derivative test?
- Find critical points using . 2. Plug critical points into . 3. Determine local min/max based on the sign of .