Find the derivative f(x) = xe^x

An architect is designing a water fountain for a park she uses the given function to model the water jet flowing from the fountain nozzles where h(x) gives the height of the water jugs in feet x feet from the starting point h(x)=-1/20x+x+15

Which of the following disjunctions is true? 4 + 4 = 16 or 6 - 5 = 11 4 · 3 = 7 or 3 - 2 = 5 8 - 5 = 13 or 7 · 2 = 12 7 - 4 = 11 or 6 + 3 = 9

If each bricks costs and he can only buy one brick how much will it cost him to get the material to put around the outside of his garden?