"计算器" "不是数字" "错误" "." "0" "1" "2" "3" "4" "5" "6" "7" "8" "9" "cos" "ln" "log" "sin" "tan" "清除" "删除" "欧拉数" "圆周率" "点" "左括号" "右括号" "余弦" "自然对数" "对数" "正弦" "正切" "加" "除" "阶乘" "乘" "幂数" "平方根" "减" "清除" "删除" "等于"