Answer:
D
Step-by-step explanation:
For it to be a function, every x value must have 1 unique y value ONLY.
In option A, you can see that the x value of 1 has 2 y values, 1 & 5. So it's not a function.
In option B, you can see that the x value of 0 has 2 y values, 0 & -4. Moreover, the x value of 4 also has 2 y values, 2 & -2. So it's not a function.
In option C, you can see that the x value of -2 has 2 y values, 4 & -4. This is not a function as well.
In option D, each x value has a unique y value that are different. So this is a function.
Answer is option D.
First, rewrite the equation so that <em>y</em> is a function of <em>x</em> :

(If you were to plot the actual curve, you would have both
and
, but one curve is a reflection of the other, so the arc length for 1 ≤ <em>x</em> ≤ 8 would be the same on both curves. It doesn't matter which "half-curve" you choose to work with.)
The arc length is then given by the definite integral,

We have

Then in the integral,

Substitute

This transforms the integral to

and computing it is trivial:

We can simplify this further to

The perimeter of the triangle is 13.56 units.
The perimeter of a shape on a coordinate plane is found by finding the distance between all points, and then adding them together. It's easier to write it out than to type so I'll attach a photo of my work.
Density is <u>mass</u>
volume
With those dimensions, the volume of the pyramid is;
V = lw(h/3)
V = (5)(6)(8/3)
V = 80 cm^3
D = <u> 40 g </u> = 1 g/cm^3
80 cm^3