For a commodity, first increase the price by 10%, and then reduce the price by 10%, is the original price more expensive or the current price more expensive? How expensive is it? Please express it in a formula that contains letters.
一种商品，先涨价10%，再降价10%，结果是原价贵还是现价贵？贵多少？请你用含有字母的式子表示出来．
<result>0.01</result>