<h2>9.</h2><h3>Given</h3>
<h3>Find</h3>
- linear approximation to the volume when the radius increases 0.4 cm
<h3>Solution</h3>
The equation for volume of a sphere is
... V = (4/3)π·r³
Differentiating gives
... dV = 4π·r²·dr
Filling in the given numbers gives
... change in volume ≈ 4π·(15 cm)²·(0.4 cm)
... = 360π cm³ ≈ 1130.97 cm³ . . . . . . volume of layer 4mm thick
<h2>11.</h2><h3>Given</h3>
- an x by x by 2x cuboid with surface area 129.6 cm²
- rate of change of x is 0.01 cm/s
<h3>Find</h3>
<h3>Solution</h3>
The area is that of two cubes of dimension x joined together. The area of each such cube is 6x², but the two joined faces don't count in the external surface area. Thus the area of the cuboid is 10x².
The volume of the cuboid is that of two cubes joined, so is 2x³. Then the rate of change of volume is
... dV/dt = (d/dt)(2x³) = 6x²·dx/dt
We know x² = A/10, where A is the area of the cuboid, so the rate of change of volume is ...
... dV/dt = (6/10)A·dx/dt = 0.6·(129.6 cm²)(0.01 cm/s)
... dV/dt = 0.7776 cm³/s
Answer:
width = 2 units
Step-by-step explanation:
If the length of a rectangle is (x) units, then that means that the width of a rectangle is x - 4 units.
the area of a rectangle is length * width
so just substitute the values that we have now.
x (length) * (x-4) width = 12 (area of rectangle)
so that gives us
x^2 - 4x =12
subtract 12 from both sides
x^2 - 4x - 12 =0
now factor this equation
x^2 + 2x - 6x -12 = 0
x(x+2) - 6(x+2) = 0
(x-6)(x+2) = 0
x = 6, or x = -2 REMEMBER THAT VALUE OF x = LENGTH, IT CANNOT BE NEGATIVE AS YOU CANT HAVE NEGATIVE VALUE OF A SIDE
length = 6, and width = 6 -4 = 2
Answer:
........
Step-by-step explanation:
.......................
Answer:
C) 8 ft
Step-by-step explanation:
you use the pythagorean theorem to find the height.
a² + b² = c²
a = radius
b = height
c = slant height
15² + h² = 17²
h = 8
