Consider the he pin$-$connected structure shown below. Consider that $E=10,000$ksi, and area of each member is $2\mathrm{.}5i{n}^2.$ The nodal coordinates and connectivity are as follows:

$\backslash$table$[[$Node$,x($inch$),Y($inch$)],[1,100,0],[2,0,0],[3,150,-86\mathrm{.}6],[4,170,70]]$

$\backslash$table$[[$Element$,\backslash$table$[[$Beginning$],[$node$]],$End node$],[1,2,1],[2,1,4],[3,3,1]]$

a$)$ Using the direct stiffness method, determine the $8x8$ global stiffness matrix $K.$ Clearly indicate its units.

b$)$ Find the displacements at node $1.$

c$)$ Find the reactions

d$)$ Find the member end forces for member $3$ and indicate whether it is in tension or compression.