# the basse of a solid S is the region enclosed by the graph of y=square root (ln x), the line x=e, and the x-axis. if the cross sections of S perpendicular to the x-axis are squares, then the volume of S is.

how do i find the side of the squares.

because i got square root(lnx) and squared it because Area of square is s^2.

then on my integrals, i would integrate it from 1 to e because that is the boundary. then what?

is what i am doing correct. i went to websites and looked in my book but i still am having trouble

## .

To find the side of the squares, you need to use the equation for the base of the solid, which is y = √lnx. To find the side of the squares, you need to evaluate the equation at the boundaries of the region (x = 1 and x = e). So, at x = 1, y = √ln1 = 0, and at x = e, y = √lne = 1. Therefore, the side of the squares is 1.

To find the volume of the solid, you need to use the formula for the volume of a solid of revolution, which is V = ∫a b πy2 dx. Substituting the equation for the base of the solid, y = √lnx, into the formula gives V = ∫1 e π(√lnx)2 dx. Evaluating the integral gives V = π(e - 1). Therefore, the volume of the solid is π(e - 1).

## Finding the side length of the squares can be done by considering a small rectangular strip within the solid S.

Let's consider a small segment dx along the x-axis and determine the length of the side of the corresponding square cross section.

The width of the strip is dx, and the height is given by y = √(ln x). Since the cross section is a square, the side length of the square is equal to the height.

So, the side length of the square is s = √(ln x).

To find the volume of S, we need to integrate the areas of all the square cross sections from x = 1 to x = e.

The volume (V) can be calculated as follows:

V = ∫[1 to e] (s^2) dx

= ∫[1 to e] (√(ln x))^2 dx

Simplifying the expression:

V = ∫[1 to e] ln x dx

Integration of ln x can be done using integration by parts:

Let u = ln x and dv = dx

Then, du = (1/x) dx and v = x

Applying the integration by parts formula:

V = [x ln x - ∫(x * (1/x) dx)] evaluated from 1 to e

V = [x ln x - ∫(dx)] evaluated from 1 to e

= [x ln x - x] evaluated from 1 to e

= (e ln e - e) - (1 ln 1 - 1)

Since ln e = 1 and ln 1 = 0, the expression simplifies to:

V = (e - e) - (0 - 1)

= 0 - (-1)

= 1

Therefore, the volume of the solid S is 1 cubic unit.

## To find the side length of the squares in the cross sections, you need to express the function in terms of x and then solve for x.

In this case, the function is given as y = √(ln x). To find the side length of the squares, you can start by noting that the height of each square is given by y.

Since the cross sections are perpendicular to the x-axis, the side length of each square will be equal to y at every value of x.

So, to find the side length, you need to solve for x in terms of y. In this case, you have y = √(ln x). To do this, you can square both sides of the equation:

y^2 = ln x

Next, you can exponentiate both sides using the inverse function of natural logarithm, which is the exponential function (e^x):

e^(y^2) = e^(ln x)

e^(y^2) = x

So, you have found x in terms of y. Therefore, the side length of each square in the cross sections is given by e^(y^2).

Now, to calculate the volume of the solid, you need to integrate the area of each square from 1 to e, with respect to y.

The area of each square is (e^(y^2))^2 = e^(2y^2). Therefore, the integral representing the volume of the solid is:

V = ∫[1 to e] e^(2y^2) dy

You can evaluate this integral to find the volume of the solid.

It's worth noting that integration techniques, such as substitution or integration by parts, may be required to evaluate the integral. If you are having trouble with the actual integration step, you might want to consult a calculus textbook or online resources for help with the specific methods required in your case.