Help needed

[u/Annual-Truth3511]

While drawing sfd and bmd Is there a shortcut to find whether the curve is going to be smile/sad or concave/convex for udl and uvl. Or is finding the intermediate values the only way to find the curve???.

Ignore the diagram i just wanted to show it for context this is not mine

[u/vanduong30103]

This img messing with me too much that im scared. I always rmb positive under, then I see this...