Answer:
(3a + 2)(a + 3)
Step-by-step explanation:
Given:





To find:
The variance. of combined set.
Solution:
Formula for variance is
...(i)
Using (i), we get




Similarly,




Now, after combining both sets, we get




Therefore, the variance of combined set is 15.4.
Answer:
791.68 cm/s
Step-by-step explanation:
The volume flow rate can be interpreted as the integral of fluid velocity over area
![\dot{V} = \int\limits^6_0 {v(r) 2\pi r} \, dr\\\dot{V} = 2\pi\int\limits^6_0 {(25-r^2)r} \, dr\\\dot{V} = 2\pi\int\limits^6_0 {25r-r^3} \, dr\\\\\dot{V} = 2\pi[12.5r^2 - r^4/4]_0^6\\\dot{V} = 2\pi(12.5*6^2 - 6^4/4 - 12.5*0 - 0)\\\dot{V} = 2\pi*126 = 791.68 cm/s](https://tex.z-dn.net/?f=%5Cdot%7BV%7D%20%3D%20%5Cint%5Climits%5E6_0%20%7Bv%28r%29%202%5Cpi%20r%7D%20%5C%2C%20dr%5C%5C%5Cdot%7BV%7D%20%3D%202%5Cpi%5Cint%5Climits%5E6_0%20%7B%2825-r%5E2%29r%7D%20%5C%2C%20dr%5C%5C%5Cdot%7BV%7D%20%3D%202%5Cpi%5Cint%5Climits%5E6_0%20%7B25r-r%5E3%7D%20%5C%2C%20dr%5C%5C%5C%5C%5Cdot%7BV%7D%20%3D%202%5Cpi%5B12.5r%5E2%20-%20r%5E4%2F4%5D_0%5E6%5C%5C%5Cdot%7BV%7D%20%3D%202%5Cpi%2812.5%2A6%5E2%20-%206%5E4%2F4%20-%2012.5%2A0%20-%200%29%5C%5C%5Cdot%7BV%7D%20%3D%202%5Cpi%2A126%20%3D%20791.68%20cm%2Fs)
According to the empirical rule, roughly 68% of the scores fall between z = -1 and z = 1
You can use a calculator to get a more approximate answer. If you have a TI calculator, you can use the "normalcdf" function to type in normalcdf(-1,1)