Skill 7
Known slopes at specific locations may be used to compute
forces or moments.

      The slope at A for the beam on the left can be found
      by summing the slopes at A for cases 1 and 2.

      If the slope at a point is known, that information can be used to
      determine unknown forces or moments. For example, if there is a
      fixed support at A, then θ_A = 0. Therefore, the following equation
      can be solved for the moment reaction M_A.