# Javascript (ES6), <s>107</s> <s>104</s> <s>100</s> 98 bytes

    p=>{s=Array(++p).join`/\\`+`
    `;for(i=p;i>2;i--)o=Array(i).join`/ `+`
    `,s+='\\'+o+o;return s+'\\/'}

_First post here!_

Uses [`Array(len)`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array#Syntax)`.`[`join(str)`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/join), similar to Ruby's [`operator*(str,len)`](http://ruby-doc.org/core-2.2.3/String.html#method-i-2A).

Ungolfed:

    len => {
    	var str = Array(++len).join `/\\` + '\n';
    
    	for (var i = len; i > 2; i--) {
    		var mid = Array(i).join `/ ` + '\n';
    		str += '\\' + mid + mid;
    	}
    
    	return str + '\\/';
    }

<br />
_Thanks!<br />
107 => 104 bytes: [@insertusernamehere](http://codegolf.stackexchange.com/users/41859/insertusernamehere)_