Check that the point (-1, 1, 2) lies on the surface given below. cos(x + y) = exz + 2 (a) View the surface as a level surface for a function f(x, y,z). Find a vector normal to the surface at (-1, 1, 2).

Which account has the highest effective annual interest rate? not necessary but show how you got your answer.a. account 1: interest is compounded quarterly at an annual rate of 4.20%.b. account 2: interest is compounded monthly at an annual rate of 4.15%.c. account 3: interest is compounded semiannually at an annual rate of 4.10%d. account 4: interest is compounded annually at a rate of 4.25%.