While computing the value of median in a continuous series (both exclusive as well as inclusive) the middle item is the (N/2) th  item and not (N+1)/2) th item. In a continuous frequency distribution a variable can have any value and as such the precise mid-point would be the (N/2)^th item. It will have 50 percent of the frequencies on one side and the other 50 per cent on the other side.
 In a continuous frequency distribution the value of the median would be in a class-interval. To get a precise value of the median we assume that the frequency of the median class is uniformly spread over the whole class-interval.