If you need a scientific calculator you’ve probably looked at OS X’s Calculator app and perhaps dismissed it as not offering everything you need. But did you know that it has a Shift button through which additional functions can be accessed? The button is up in the top left corner. You can also simply press Shift on the keyboard to see the alternative functions. Give it a try! And don’t forget that the app has also a Reverse Polish notation (RPN) mode available on the View menu.