the truss has two supports $($point A is a pin and point B is a roller$).$ The geometry of the

problem is described by the lengths $(!$ and $"),$ whereas the external loads have magnitudes $$#

and $$$ and their directions are given by the angles $$# and $$$ $,$ respectively. All the members of

the truss are numbered below. The parameters of the problem are $$# $,$# $,$$ $,$$ $,!,$ and $".$

Fig. $1$

$1.$ Determine the external reactions at the supports as a function of these parameters $[10$p$].$ Fig. $1$