7. Calculate the value of the limit, if it exists, or show that it does not exist. lim xyz (x,))-(123 x-y+2 8. Given the vector field G(x, y,z) = ev+2= (i + x j + 2xk) : a) Show G(x, y,z) is conservative without finding a potential function. b) Determine a potential function. 9. Determine the value of the integral Lyas Where & is the cubic cylinder x = y' where 0