A spherical shell whose inner radius is 2 cm and whose outer radius is 8 cm is made of material of varying density. At a point {x, y, z}, the density of the material is 0.39 times the square of the distance to the center of the sphere. Assume all the air has been pumped out of the hollow interior. Does the shell sink or float in water?

Density is 16.11 units, If it is less than the density of water in the same units, the sphere will float.

Step-by-step explanation:

We have to:

Mass of shell at distance r from:

Density = mass / volume, if we solve for mass we have:

Mass = volume * density

replacing:

Mass = (4 * pi * (r ^ 2) * dr) * (0.39r ^ 2)

Mass = 1.68 * pi * r ^ 4 * dr

Mass = 1.68 * pi integral from 2 to 8 of {r ^ 4 * dr}

Mass = 1.68 * 3.14 * (r ^ 5) / 5 when r equals 2 to 8, replacing:

Mass = 1.68 * 3.14 * [(8 ^ 5/5 - (2) ^ 5/5]

Mass = 34537.79

Now the volume would be: (4/3) * pi * r ^ 3, we replace:

(4/3) * 3.14 * 8 ^ 3 = 2143.57

Density = 34537.79 / 2143.57 = 16.11 units

If it is less than the density of water in the same units, the sphere will float.

guess at question:

a vertical line intersects the graph of g(x,y) = 0 at two points. what conclusion follows about the function f(x) implicitly defined by g(x,f(x)) = 0?

the domain of f(x) cannot include the x coordinate of any such vertical line.

informally, f(x) is not a function, and

g(x,y)=0 cannot be solved for y uniquely.

the relation r = {(x,y) such that g(x,y) = 0} is a function if

for all (a,b) ∊ r and (c,d) ∊ r, a=c implies b=d.

step-by-step explanation:

the polynomial is a perfect square trinomial of the form a^2-2ab+b^2:

option a. true

step-by-step explanation:

9x^2-12x+4

comparing with the form a^2-2ab+b^2

1.) a^2=9x^2

solving for a: square root both sides of the equation:

sqrt(a^2)=sqrt(9x^2)

a=sqrt(9) sqrt(x^2)

a=3x

2.) b^2=4

solving for b: square root both sides of the equation:

sqrt(b^2)=sqrt(4)

b=2

to be a perfet square trinomial 2ab must be equal to 12x. let's check:

2ab = 2 (3x) (2)

2ab = 12x

correct