RPN (54 %) RPN or reverse Polish notation is the postfix arithmetic expression where operator is put after the operands such as 1 2 + (which means 1 + 2 or 3). You have learned on how to evaluate a valid postfix expression, how to tell if a postfix expression is valid or not, how to convert a valid infix expression to a valid postfix expression, manually, or through a stack etc. 1. (30 %) Convert infix to postfix (a) (15%) Convert this infix expression to postfix. You do not have to follow the steps of the algorithm in the book to do the conversion (you can do manually or by inspection, or by computer programming etc.) (this expression is four ls with three minus signs separating them) 1 - 1 - 1 - 1 (b)(8%) After conversion, evaluate the postfix expression. Show the step by step calculation. (c)(7%) Verify that agrees with the result of using the original infix expression. 2. (24%) Evaluate the following two postfix expressions. Show the calculations step by step. (a)(12%) 1 1 1 1 - - (there is one minus sign after the first two ls' then two ls followed by two minus signs) (b)(12%)1 1 1 1 (there are four ls followed by three minus signs)