1. The problem statement, all variables and given/known data "A lawn sprinkler is constructed in such a way that d[itex]\theta[/itex]/dt is constant, where [itex]theta[/itex] ranges between 45 degrees and 135 degrees. The distance the water travels horizontally is [tex]x=v^2sin(2\theta)/32[/tex] where v is the speed of the water. Find dx/dt and explain why this lawn sprinkler does not water evenly. What part of the lawn receives the most water? 2. Relevant equations 3. The attempt at a solution I took the derivative of the function getting, [tex]dx/dt=(2v*sin2\theta(dx/dt) +2v^2cos2\theta(dx/dt))32[/tex] I made a mistake because I can factor out dx/dt, then dividing both sides by dx/dt sets the equation to 1 but I don't want that. Where am I making my mistake? It seems to me that my differentiation was correct but I must have made a mistake. If you want I'll walk through it. This answer isn't the same as the one in the back of the book either, I avoid looking at the back usually and forget the answers are even there.