Calculus 1 : Area

Study concepts, example questions & explanations for Calculus 1

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Example Questions

Example Question #91 : How To Find Area Of A Region

Find the area under the curve drawn by the function  on the interval of  to .

Possible Answers:

Correct answer:

Explanation:

In order to find the area under  on the interval of  to , you must evaluate the definite integral

 

 

First, integrate the function.

Then, substitute values for .

Finally, evaluate while cancelling negative signs.

Example Question #171 : Regions

What is the area below the curve  , above the -axis, and between  and ?

Possible Answers:

Correct answer:

Explanation:

The area described is the integral 

.

This can be evaluated using the linear properties of integrals and the Power Law, which says

.

Thus the integral above is equal to

.

Example Question #172 : Regions

Find the area of the region between the graphs of  and  from  to .

The two functions are increasing during the interval

Possible Answers:

Correct answer:

Explanation:

To the find the area of the region between  and , one needs to first figure out which function is above the other in the interval . Plug in  and  into each function to check which one has the higher value at these respective points.

 has a higher value than at both of these x-values, and since both functions are increasing during this interval, we can conclude that  is above  during this interval.

After that, set the definite integral 

.

Using the general rule for integrals,

and for exponential functions,

on our function we get

  from  to .

This equals to 

.

Example Question #3051 : Functions

Find the area of the region created between the graphs of  and  between  and .

Possible Answers:

Correct answer:

Explanation:

Area of a region between two graphs  and , and between two  values  and  can be given as

Since we want to find the area between  and  between  and ,

we can set this up as one definite integral. 

We can ignore the value until we have a numerical answer.

First, we know that by the sum rule

By the power rule, we know that

, where are constants and  is a variable.

Therefore,

We also know as an identity that

, when 

Therefore,

We also know that for definite integrals,

, where 

In our case, 

 

Example Question #173 : Regions

Find the area of the region between the curve of the function

 

and the -axis on the interval .

Possible Answers:

 square units

 square units

 square units

 square units

Correct answer:

 square units

Explanation:

In order to find the area of the region between the curve of the function and the x-axis on the interval [,], we solve for the integral

.

For this problem the integral becomes

And since the fuction is always positive on the interval, the integral becomes

.

When taking the integral, we will use the inverse power rule which states,

 .

Applying this rule we get

 .

And by the corollary of the First Fundamental Theorem of Calculus

 .

As such, the area is 

 square units.

Example Question #174 : Regions

Find the area of the region between the curve of the function

and the -axis on the interval .

Possible Answers:

 square units

 square units

 square units

 square units

Correct answer:

 square units

Explanation:

In order to find the area of the region between the curve of the function and the x-axis on the interval , we solve for the integral

.

For this problem the integral becomes

.

And since the function is always positive on the interval, the integral becomes

.

When taking the integral, we will use the inverse power rule which states,

 .

Applying this rule we get

 .

And by the corollary of the First Fundamental Theorem of Calculus

 .

As such, the area is 

 square units.

Example Question #95 : How To Find Area Of A Region

What is the area of the region beneath the curve defined by the function  to the right of the y-axis?

Possible Answers:

Correct answer:

Explanation:

For the region to the right of the y-axis, the range of x is .  The next step is to find the integral of the function:

The method of integration by parts will serve here:

Now,  converges to zero; however, to determine what  conveges to, use L'Hopital's Rule:

Since  can be rewrittena s  and both the numerator and denominator approach  as x does:

 

Example Question #91 : Area

Which of the following integrals represents the area of the rectangle formed by the points , , , and ?

Possible Answers:

Correct answer:

Explanation:

The function that bounds a rectangle is a horizontal line.

In this case, , so the area of the shape is just the integral of this line over the bounds of the x-axis, which in this case is 3 and 7 since the rectangle starts at 3 and ends at 7.

Thus, is the solution. 

Example Question #176 : Regions

Find the area of the region bounded by the curve  and the -axis over the interval .

Possible Answers:

Correct answer:

Explanation:

The area of the region bounded underneath by the x-axis can be found by integrating the function

over the specified interval of :

To integrate use the rule,

.

Applying this rule to our function we find the following.

Example Question #177 : Regions

Find the area of the region bounded by the functions , and on the left by the -axis.

Possible Answers:

Correct answer:

Explanation:

To find the area of the region between the functions  , the first step will be to determine the lower and upper x bounds. We're told the region is bounded by the y-axis on the left, so . The upper x-bound will be where the two functions intersect:

For the value of , each of the functions equals .

Over the interval of , so the area of the region can be determined by the integral:

Use the following rules to integrate the function:

 and 

Applying the above rules we get,

.

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