Since lines that meet at some point have an angle. And if parallel lines meet at infinity, then that what is the angle of two parallel lines that meet at infinity?
My teacher told me that two parallel lines have a point of intersection, it is called Point at infinity. But I I can't understand how it can be true or how was it proved, can someone explain this to me?  Thank you.
I don't know what to do with this. Nothing works. I hope somebody can help me to find a decision $$n!\leq {\left(\frac{n+1}{2}\right)}^{n}$$ Implement numbering scheme like A,B,C... AA,AB,... AAA..., similar to converting a number to radix26 I want to implement numbering scheme like Microsoft Word uses for numbering.  first one gets = A,next is  B, next is C, .... then AA, then AB,....and so on.  as shown below   A        B  C  .   .  AA  AB  AC  .  .  AAA  AAB  ....   '=>' here means converted to.  some examples:       1 =&gt; A 26 =&gt; Z 27 =&gt; AA 52 =&gt; AZ 53 =&gt; BA   and heres the code for it:     var convertToNumberingScheme = function(n){         var x = n-1,             r26 = x.toString(26),             baseCharCode = "A".charCodeAt(0);          var arr = r26.split(''),             len = arr.length;          var newArr =arr.map(function(val,i){             val = parseInt(val,26);              if( (i === 0) &amp;&amp; ( len &gt; 1)){                 val = val-1;             }              return String.fromCharCode(baseCharCode + val);         });         return newArr.join('');     }   It seems to work fine, but any ideas if there are some potential bugs or ways to  optimize this. Please Join Us in Welcoming Our New Meta Stack Exchange Moderators! In the NEW CANON why don't the Rebels abandon Yavin 4 before the Death Star Arrives? Where's the Strangedupe blog post? 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