Aparticle moves on a coordinate line with acceleration startfraction d squared s over dt squared endfraction equals 45 startroot t endroot minus startfraction 21 over startroot t endroot endfraction d2s dt2=45t− 21 t, subject to the conditions that startfraction ds over dt endfraction equals 6 ds dt=6 and sequals=1818 when t equals 1t=1. find the velocity v equals startfraction ds over dt endfractionv= ds dt in terms of t and the position s in terms of t.