The shaft of radius c is subjected to a distributed torque t, measured as torque/unit length of shaft. Shaft A B of length L, fixed at B, with x measured from B. Torque t = t sub 0 [1 + (x over L) squared], from t sub 0 at B to 2 t sub 0 at A. The shear modulus is G. Part A Determine the angle of twist at end A. Express your answer as an expression in terms of the variables t0, L, c, and G and any necessary constants.