### All Precalculus Resources

## Example Questions

### Example Question #1 : Rate Of Change Problems

Find the average rate of change of the function over the interval from to .

**Possible Answers:**

**Correct answer:**

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 .

**Possible Answers:**

**Correct answer:**

We use the average rate of change formula, which gives us .

Now , and .

Therefore, the answer becomes .

### Example Question #3 : 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 .

**Possible Answers:**

**Correct answer:**

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 #1 : 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.

**Possible Answers:**

**Correct answer:**

Since , we see that this equals. Now let's examine . which simplifies to .

Therefore the average rate of change formula gives us .

### Example Question #1 : 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.

**Possible Answers:**

**Correct answer:**

Thus the average rate of change formula yields .

This implies that the demand drops as the price increases.

### Example Question #1 : Rate Of Change Problems

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.

**Possible Answers:**

**Correct answer:**

.

.

Hence, the average rate of change formula gives us .

### Example Question #1 : Rate Of Change Problems

Find the average rate of change of between and .

**Possible Answers:**

**Correct answer:**

The solution will be found by the formula .

Here gives us , and .

Thus, we find that the average rate of change is .

### Example Question #2 : Rate Of Change Problems

Find the average rate of change of over the interval from to .

**Possible Answers:**

**Correct answer:**

The average rate of change will be .

.

.

This gives us .

### Example Question #1 : Rate Of Change Problems

Find the average rate of change of over the interval from to .

**Possible Answers:**

**Correct answer:**

The average rate of change will be .

Now.

We also know .

So we have .

### Example Question #10 : Rate Of Change Problems

Why can we make an educated guess that the average rate of change of , between and would be ?

**Possible Answers:**

We know is symmetrical on that interval.

We know is a polynomial.

We know is vertical on that interval.

We know is odd on that interval.

We know is horizontal on that interval.

**Correct answer:**

We know is symmetrical on that interval.

Because is symmetrical over the y axis, it increases exactly as much as it decreases on the interval from to . Thus the average rate of change on that interval will be .