Pre Calc help?? A few questions?

1. Show whether x + y 2 = 3 is a function.








2. If a rock falls from a height of 30 meters on Earth, the height H (in meters) after x seconds is approximately H(x) = 30 - 4.9x^2 . If a rock is dropped from 30 meters, how long will it take for the rock to hit the ground? Round to the nearest hundredth of a second.











3. Using your knowledge of transformations, write a function whose graph is the graph of f(x) = (square root of)x shifted up 3 units and reflected across the y axis.








4. You have $10,000 you would like to invest. You are comparing three time-deposit accounts, all of which require you to deposit your money for a period of two years before withdrawing it. The first account has an annual interest rate of 4.9%, and interest is compounded quarterly. The second has an interest rate of 4.7% with interest compounded monthly. The third account offers an interest rate of 4.4%, with interest compounded continuously. Determine how much money you would have after two years for all three accounts, showing all work. Then state which of the three accounts is the best investment option.|||1. doesn't make sense





2. it hits the ground when h = 0 = 30 - 4.9x^2 so x = 鈭?30/4.9)





3. y = 鈭歺


to move the graph up by 3 you need to move the origin down by 3 so replace y with y-3


so y-3 = 鈭歺


to reflect the graph about the y axis you need to flip the x axis over so replace x with -x


so y-3 = 鈭?-x)


or


y = 3 + 鈭?-x)


is the answer





4.


10000(1 + 0.049/4)^(4*2) = $11023.06 .......best





10000(1 + 0.047/12)^(12*2) = $10983.58





10000*e^(0.044*2) = $10919.88





,,.,.,.|||I'll answer the first one and let others jump in on the rest. Firstly, I think you mean x + y^2 = 3 and probably y is intended to be the dependent variable and x the independent variable.





For this to be a function, each value of x should only result in one corresponding value of y. So if x = -1 in this case, you get y^2 = 4, which could lead to either y = 2 or -2. So this fails to be a function.





On the other hand, if you made x the dependent variable and y the independent one, things change in that for any one value of y you choose, there will only be one corresponding value of x. So that would be a function.