78/3/4=78x4/3=104
So, the answer is 104
Answer:
About the x axis
![V = 4\pi[ \frac{x^5}{5}] \Big|_0^2 =4\pi *\frac{32}{5}= \frac{128 \pi}{5}](https://tex.z-dn.net/?f=%20V%20%3D%204%5Cpi%5B%20%5Cfrac%7Bx%5E5%7D%7B5%7D%5D%20%5CBig%7C_0%5E2%20%3D4%5Cpi%20%2A%5Cfrac%7B32%7D%7B5%7D%3D%20%5Cfrac%7B128%20%5Cpi%7D%7B5%7D)
About the y axis
![V = \pi [4y -y^2 +\frac{y^3}{12}] \Big|_0^8 =\pi *\frac{32}{3}= \frac{32 \pi}{3}](https://tex.z-dn.net/?f=%20V%20%3D%20%5Cpi%20%5B4y%20-y%5E2%20%2B%5Cfrac%7By%5E3%7D%7B12%7D%5D%20%5CBig%7C_0%5E8%20%3D%5Cpi%20%2A%5Cfrac%7B32%7D%7B3%7D%3D%20%5Cfrac%7B32%20%5Cpi%7D%7B3%7D)
About the line y=8
![V = \pi [64x -\frac{32}{3}x^3 +\frac{4}{5}x^5] \Big|_0^2 =\pi *(128-\frac{256}{3} +\frac{128}{5})= \frac{1024 \pi}{5}](https://tex.z-dn.net/?f=%20V%20%3D%20%5Cpi%20%5B64x%20-%5Cfrac%7B32%7D%7B3%7Dx%5E3%20%2B%5Cfrac%7B4%7D%7B5%7Dx%5E5%5D%20%5CBig%7C_0%5E2%20%3D%5Cpi%20%2A%28128-%5Cfrac%7B256%7D%7B3%7D%20%2B%5Cfrac%7B128%7D%7B5%7D%29%3D%20%5Cfrac%7B1024%20%5Cpi%7D%7B5%7D)
About the line x=2
![V = \frac{\pi}{2} [\frac{y^2}{2}] \Big|_0^8 =\frac{\pi}{4} *(64)= 16\pi](https://tex.z-dn.net/?f=%20V%20%3D%20%5Cfrac%7B%5Cpi%7D%7B2%7D%20%5B%5Cfrac%7By%5E2%7D%7B2%7D%5D%20%5CBig%7C_0%5E8%20%3D%5Cfrac%7B%5Cpi%7D%7B4%7D%20%2A%2864%29%3D%2016%5Cpi)
Step-by-step explanation:
For this case we have the following functions:
![y = 2x^2 , y=0, X=2](https://tex.z-dn.net/?f=%20y%20%3D%202x%5E2%20%2C%20y%3D0%2C%20X%3D2)
About the x axis
Our zone of interest is on the figure attached, we see that the limit son x are from 0 to 2 and on y from 0 to 8.
We can find the area like this:
![A = \pi r^2 = \pi (2x^2)^2 = 4 \pi x^4](https://tex.z-dn.net/?f=%20A%20%3D%20%5Cpi%20r%5E2%20%3D%20%5Cpi%20%282x%5E2%29%5E2%20%3D%204%20%5Cpi%20x%5E4)
And we can find the volume with this formula:
![V = \int_{a}^b A(x) dx](https://tex.z-dn.net/?f=%20V%20%3D%20%5Cint_%7Ba%7D%5Eb%20A%28x%29%20dx)
![V= 4\pi \int_{0}^2 x^4 dx](https://tex.z-dn.net/?f=%20V%3D%204%5Cpi%20%5Cint_%7B0%7D%5E2%20x%5E4%20dx)
![V = 4\pi [\frac{x^5}{5}] \Big|_0^2 =4\pi *\frac{32}{5}= \frac{128 \pi}{5}](https://tex.z-dn.net/?f=%20V%20%3D%204%5Cpi%20%5B%5Cfrac%7Bx%5E5%7D%7B5%7D%5D%20%5CBig%7C_0%5E2%20%3D4%5Cpi%20%2A%5Cfrac%7B32%7D%7B5%7D%3D%20%5Cfrac%7B128%20%5Cpi%7D%7B5%7D)
About the y axis
For this case we need to find the function in terms of x like this:
![x^2 = \frac{y}{2}](https://tex.z-dn.net/?f=%20x%5E2%20%3D%20%5Cfrac%7By%7D%7B2%7D)
but on this case we are just interested on the + part
as we can see on the second figure attached.
We can find the area like this:
![A = \pi r^2 = \pi (2-\sqrt{\frac{y}{2}})^2 = \pi (4 -2y +\frac{y^2}{4})](https://tex.z-dn.net/?f=%20A%20%3D%20%5Cpi%20r%5E2%20%3D%20%5Cpi%20%282-%5Csqrt%7B%5Cfrac%7By%7D%7B2%7D%7D%29%5E2%20%3D%20%5Cpi%20%284%20-2y%20%2B%5Cfrac%7By%5E2%7D%7B4%7D%29)
And we can find the volume with this formula:
![V = \int_{a}^b A(y) dy](https://tex.z-dn.net/?f=%20V%20%3D%20%5Cint_%7Ba%7D%5Eb%20A%28y%29%20dy)
![V= \pi \int_{0}^8 2-2y +\frac{y^2}{4} dy](https://tex.z-dn.net/?f=%20V%3D%20%5Cpi%20%5Cint_%7B0%7D%5E8%202-2y%20%2B%5Cfrac%7By%5E2%7D%7B4%7D%20dy)
![V = \pi [4y -y^2 +\frac{y^3}{12}] \Big|_0^8 =\pi *\frac{32}{3}= \frac{32 \pi}{3}](https://tex.z-dn.net/?f=%20V%20%3D%20%5Cpi%20%5B4y%20-y%5E2%20%2B%5Cfrac%7By%5E3%7D%7B12%7D%5D%20%5CBig%7C_0%5E8%20%3D%5Cpi%20%2A%5Cfrac%7B32%7D%7B3%7D%3D%20%5Cfrac%7B32%20%5Cpi%7D%7B3%7D)
About the line y=8
The figure 3 attached show the radius. We can find the area like this:
![A = \pi r^2 = \pi (8-2x^2)^2 = \pi (64 -32x^2 +4x^4)](https://tex.z-dn.net/?f=%20A%20%3D%20%5Cpi%20r%5E2%20%3D%20%5Cpi%20%288-2x%5E2%29%5E2%20%3D%20%5Cpi%20%2864%20-32x%5E2%20%2B4x%5E4%29)
And we can find the volume with this formula:
![V = \int_{a}^b A(x) dx](https://tex.z-dn.net/?f=%20V%20%3D%20%5Cint_%7Ba%7D%5Eb%20A%28x%29%20dx)
![V= \pi \int_{0}^2 64-32x^2 +4x^4 dx](https://tex.z-dn.net/?f=%20V%3D%20%5Cpi%20%5Cint_%7B0%7D%5E2%2064-32x%5E2%20%2B4x%5E4%20dx)
![V = \pi [64x -\frac{32}{3}x^3 +\frac{4}{5}x^5] \Big|_0^2 =\pi *(128-\frac{256}{3} +\frac{128}{5})= \frac{1024 \pi}{5}](https://tex.z-dn.net/?f=%20V%20%3D%20%5Cpi%20%5B64x%20-%5Cfrac%7B32%7D%7B3%7Dx%5E3%20%2B%5Cfrac%7B4%7D%7B5%7Dx%5E5%5D%20%5CBig%7C_0%5E2%20%3D%5Cpi%20%2A%28128-%5Cfrac%7B256%7D%7B3%7D%20%2B%5Cfrac%7B128%7D%7B5%7D%29%3D%20%5Cfrac%7B1024%20%5Cpi%7D%7B5%7D)
About the line x=2
The figure 4 attached show the radius. We can find the area like this:
![A = \pi r^2 = \pi (\sqrt{\frac{y}{2}})^2 = \pi\frac{y}{2}](https://tex.z-dn.net/?f=%20A%20%3D%20%5Cpi%20r%5E2%20%3D%20%5Cpi%20%28%5Csqrt%7B%5Cfrac%7By%7D%7B2%7D%7D%29%5E2%20%3D%20%5Cpi%5Cfrac%7By%7D%7B2%7D)
And we can find the volume with this formula:
![V = \int_{a}^b A(y) dy](https://tex.z-dn.net/?f=%20V%20%3D%20%5Cint_%7Ba%7D%5Eb%20A%28y%29%20dy)
![V= \frac{\pi}{2} \int_{0}^8 y dy](https://tex.z-dn.net/?f=%20V%3D%20%5Cfrac%7B%5Cpi%7D%7B2%7D%20%5Cint_%7B0%7D%5E8%20y%20dy)
![V = \frac{\pi}{2} [\frac{y^2}{2}] \Big|_0^8 =\frac{\pi}{4} *(64)= 16\pi](https://tex.z-dn.net/?f=%20V%20%3D%20%5Cfrac%7B%5Cpi%7D%7B2%7D%20%5B%5Cfrac%7By%5E2%7D%7B2%7D%5D%20%5CBig%7C_0%5E8%20%3D%5Cfrac%7B%5Cpi%7D%7B4%7D%20%2A%2864%29%3D%2016%5Cpi)
Answer: The number is 0.75 or 3/4
Step-by-step explanation:
let x = the number.
Now set up an equation: The product of a number (x) and -4 = -4x. So -4x is subtracted from the number - x. x-(-4x)
Then, that equals 3 more than the number (x) = x+3
So the equation is x-(-4x)=x+3.
Then, solve the equation!
x-(-4x)=x+3
x+4x=x+3 (Distribute the negative to the parentheses)
5x=x+3 (Combine like terms)
4x=3 (Get the Xs on one side by subtracting x from both sides)
x=0.75 or 3/4 (divide by the coefficiant, 4, on both sides)
Answer:
Step-by-step explanation: