Do you mean , or ? Putting careful parentheses around all function arguments is a very good way to enhance clarity of expressions.
What kind of calculator do you have? If it's HP with the reverse Polish, let some other (poor) fellow help you out. If it's a more normal calculator, especially if it allows parentheses, you should be able to enter it more or less as it shows up on the page. Also, I would highly recommend you double-check to see if the calculator is in degrees or radian mode. I'm assuming the 30 is degrees?