Symmetric loading vs antisymmetric loading

[fonseh]

Homework Statement

For the circled beam , we can see that for both cases , the load are loaded in the same way ... Why the M / EI diagram for the first case is different from the second case ? Why for the first case , it's symmetric loading ? For the second case , it's antisymmetric loading ?

Homework Equations

The Attempt at a Solution

I think the second case is wrong . Only the first case make sense . From the figure , we can see that the load P is applied at the midspan of AB and CD . So . it's symmetric loading , am i right ?

 

[PhanthomJay]

The loading is not symmetric in case 2.
Why?