1. The problem statement, all variables and given/known data derive the equation for the bulk modulus, K = E/3(1 - 2v), where v is poisson's ratio. 2. Relevant equations E = stress/e, where e is strain 3. The attempt at a solution e_v = e_x + e_y + e_z e_y = e_z = -v*e_x e_v = (1 - 2v)*e_x K = stress/e_v therefore K = stress/[(1 - 2v)*e_x] i am out by a factor of 1/3. where have i gone wrong?