Define a SCHEME function, unzip, which takes a list of pairs ((a1 .b1 ). . .(an .bn )) and returns a pair consisting of the two lists (a1 . . . an ) and (b1 . . . bn ). Note that these functions are not exactly inverses of each other, since zip takes its lists as a two arguments, while unzip produces a pair of lists. Finally, it is wise to realize how SCHEME prints out a pair of lists. Consider the statement (cons (list 1 2) (list 3 4)) which denotes a pair of lists. It prints as ((1 2) 3 4).

Function tipcalculate (slider, bill){  var tip = document.getelementbyid('tipamount');   var slideval = document.getelementbyid('slideval');   var bill = document.getelementbyid(bill).value;   var prcnt = slider * .01;       if (bill == null || bill == '') {      tip.innerhtml = ' enter an amount';       return false;   }  if(isnan(bill)) {      tip.innerhtml = ' enter a number';       return false;   }  if(bill > = 0){      tip.innerhtml = '$' + (bill * prcnt) .tofixed(2);   slideval.innerhtml = slider + '%';   }}