Which order of differentiation will calculate f_xy faster: x first or y first? Try to answer without writing anything down.

a. ƒ(x, y) = x sin y + e^y

b. ƒ(x, y) = 1/x

c. ƒ(x, y) = y + (x/y)

d. ƒ(x, y) = y + x²y + 4y³ - ln ( y² + 1)

e. ƒ(x, y) = x² + 5xy + sin x + 7e^x

f. ƒ(x, y) = x ln xy