Two masses m and M are attached with strings as shown. For the system to be in equilibrium we have

mg = 2Tsin 450       mg = 2TT1cos θ = T cos 450T1cosθ = T2 =mg2{∵ T = mg2}Further, Mg + T cos 450 = T1 sin θT1 sin θ = Mg + mg212T1sin θ = Mg+mg2tan θ = Mg+mg2mg2 = 1+2Mm