Determine the force in members BC$,$ CD$,$ BD$,$ and AD of the truss and state if each member is in tension or compression. Set P$1=45$kN$,$ P$2=30$kN$.(6-2)[$BC$=0$; CD$=45$kN $($C$)$; BD$=75$kN $($T$)$; AD$=90$kN $($C$)]$