$$\int_0^4 \lfloor x/2 \rfloor \ d(x-\lfloor x \rfloor)$$
I don't get how we convert the given differential element into normal dx differential element.
I plotted the graphs of $$\lfloor x/2 \rfloor$$ and $$x-\lfloor x \rfloor$$ and tried to integrate along the graph of differential element function according to it answer comes to 0.
But the answer comes to 2
Just help in conversion of differential element the rest I can do