It is C. The first part is raised to the 2nd power. so it goes first since that is the highest. then the -20x because variables are understood to the power of 1, while normal numbers are understood to the power of 0. so the order is highest to lowest (2,1,0)
Answer:
Parallel: extending in the same direction, everywhere equidistant.
Perpendicular: ar an angle of 90 to a givin line, plane or surface.
Answer:
The magnitude is 
The direction is 
i.e toward the x-axis
Step-by-step explanation:
From the question we are told that
The function is 
The point considered is 
Generally the maximum rate of change of f at the given point and the direction is mathematically represented as
![\Delta f(x,y) = [\frac{\delta f(x,y)}{\delta x } i + \frac{\delta f(x,y)}{\delta y } j ]](https://tex.z-dn.net/?f=%5CDelta%20f%28x%2Cy%29%20%3D%20%20%5B%5Cfrac%7B%5Cdelta%20%20f%28x%2Cy%29%7D%7B%5Cdelta%20x%20%7D%20i%20%2B%20%5Cfrac%7B%5Cdelta%20%20f%28x%2Cy%29%7D%7B%5Cdelta%20y%20%7D%20j%20%20%5D)
![\Delta f(x,y) = [\frac{\delta (9sin(xy))}{\delta x} i + \frac{\delta (9sin(xy))}{\delta y} i ]](https://tex.z-dn.net/?f=%5CDelta%20f%28x%2Cy%29%20%3D%20%20%5B%5Cfrac%7B%5Cdelta%20%20%289sin%28xy%29%29%7D%7B%5Cdelta%20x%7D%20i%20%20%2B%20%5Cfrac%7B%5Cdelta%20%20%289sin%28xy%29%29%7D%7B%5Cdelta%20y%7D%20i%20%20%20%5D)
![\Delta f(x,y) = [9y cos (x,y) i + 9xcos (x,y) j]](https://tex.z-dn.net/?f=%5CDelta%20f%28x%2Cy%29%20%3D%20%5B9y%20cos%20%28x%2Cy%29%20i%20%2B%20%209xcos%20%28x%2Cy%29%20j%5D)
At
![\Delta f (0,8) = [9(8) cos(0* 8)i + 9(8) sin(0* 8)j ]](https://tex.z-dn.net/?f=%5CDelta%20%20f%20%280%2C8%29%20%3D%20%20%5B9%288%29%20cos%280%2A%208%29i%20%20%2B%209%288%29%20sin%280%2A%208%29j%20%20%5D)
We are given equation g = 748u, where g is the total number of gallons of water used and u is the number of units.
We can see that the number of units of water being used by customers.
The number of units of water doesn't depend on the total number of gallons of water used.
Therefore, the number of units u is an independent variable.
The value of the total number of gallons is totally depends on the number of units used.
Therefore, the total number of gallons of water used g is a dependent variable.
So, we can conclude following statements:
1) g is the dependent variable.
2) u is the independent variable.
