All Precalculus Resources
Example Questions
Example Question #2 : Pre Calculus
The function is such that
When you take the second derivative of the function , you obtain
What can you conclude about the function at ?
The point is an absolute maximum.
The point is a local maximum.
The point is an inflection point.
The point is an absolute minimum.
The point is a local minimum.
The point is an inflection point.
We have a point at which . We know from the second derivative test that if the second derivative is negative, the function has a maximum at that point. If the second derivative is positive, the function has a minimum at that point. If the second derivative is zero, the function has an inflection point at that point.
Plug in 0 into the second derivative to obtain
So the point is an inflection point.
Example Question #5 : Pre Calculus
Consider the function
Find the maximum of the function on the interval .
Notice that on the interval , the term is always less than or equal to . So the function is largest at the points when . This occurs at and .
Plugging in either 1 or 0 into the original function yields the correct answer of 0.
Example Question #1 : Derivatives
In what -intervals are the relative minimum and relative maximum for the function below?
A cubic function will have at most one relative minimum and one relative maximum. We can determine the zeros be factoring at . From then we only need to determine if the graph is positive or negative in-between the zeros.
The graph is positive between and (plug in ) and negative between 0 and 4 (plug in ). This can also be seen from the graph.
Example Question #1 : Derivatives
What is the minimum of the function ?
The vertex form of a parabola is:
where is the vertex of the parabola.
The function for this problem can be simplified into vetex form of a parabola:
,
with a vertex at .
Since the parabola is concave up, the minimum will be at the vertex of the parabola, which is at .
Example Question #1 : Derivatives
Find the average rate of change of the function over the interval from to .
The average rate of change will be found by .
Here, , and .
Now, we have .
Example Question #2 : Rate Of Change Problems
Let a function be defined by .
Find the average rate of change of the function over .
We use the average rate of change formula, which gives us .
Now , and .
Therefore, the answer becomes .
Example Question #2 : Rate Of Change Problems
Suppose we can model the profit, , in dollars from selling items with the equation .
Find the average rate of change of the profit from to .
We need to apply the formula for the average rate of change to our profit equation. Thus we find the average rate of change is .
Since , and , we find that the average rate of change is .
Example Question #3 : Rate Of Change Problems
Let the profit, , (in thousands of dollars) earned from producing items be found by .
Find the average rate of change in profit when production increases from 4 items to 5 items.
Since , we see that this equals. Now let's examine . which simplifies to .
Therefore the average rate of change formula gives us .
Example Question #2 : Rate Of Change Problems
Suppose that a customer purchases dog treats based on the sale price , where , where .
Find the average rate of change in demand when the price increases from $2 per treat to $3 per treat.
Thus the average rate of change formula yields .
This implies that the demand drops as the price increases.
Example Question #2 : Derivatives
A college freshman invests $100 in a savings account that pays 5% interest compounded continuously. Thus, the amount saved after years can be calculated by .
Find the average rate of change of the amount in the account between and , the year the student expects to graduate.
.
.
Hence, the average rate of change formula gives us .