A: You just need to enter the serial number you got from the Google Play Store. Q: Get top three values from the collection in mongodb using php Here is my code: $mongo = new MongoClient(“localhost”);$db = $mongo->selectDb(“starterwork”);$collection = $db->teams;$team=”ustc”; $team_reu=”tteam”;$collection->find(array(“_id”=>$team_reu),array(“n”=>1),array(“_id”=>true,”teams.TeamSize.size”=>true)); The code is working properly. How can i get only top 3 teams based on the number of points of the team and save it in$top_teams A: You can use limit and take to change the number of elements returned by a single collection. The 3rd element is returned by default. So to retrieve just the top 3 you use the limit parameter. $collection->find(array(“_id”=>$team_reu),array(“n”=>1),array(“_id”=>true,”teams.TeamSize.size”=>true)); $top_teams =$collection->take(3); If this isn’t what you wanted, you need to describe what you are trying to accomplish in more detail. Update: As mentioned in the comments, the second parameter ($options) on take() specifies the _id field.$collection->find(array(“_id”=>$team_reu),array(“n”=>1),array(“_id”=>true,”teams.TeamSize.size”=>true));$top_teams = $collection->take(3,”teams._id”); Q: Does the assumption of$y’ = 0$imply that$y$is constant? Suppose$y’ = 0$. That is,$\frac{dy}{dx} = 0$. Are$y$and$x$constant? And I don’t even know if$y$and$x$can take different values simultaneously. My main question is: what are the derivatives of the equation$y’ = 0$? A: Yes, for any given$x$, if$y\$ is a