In: Economics
Write down expressions for the first-order partial derivatives, ?z and ?z for ?x ?y (a)z=x2 +4y5 (b)z=3x3 ?2ey (c)z=xy+6y (d)z=x6y2 +5y3
a.
z = x^2 + 4y^5
(dz/dx) = Partial derivative of z with respect to x
= 2x ^(2 – 1) + 0
= 2x [Answer]
z = x^2 + 4y^5
(dz/dy) = Partial derivative of z with respect to y
= 0 + (4 × 5) y ^(5 – 1)
= 20y^4 [Answer]
c.
z = xy + 6y
(dz/dx) = Partial derivative of z with respect to x
= y × x ^(1 – 1) + 0
= y × x ^0
= y × 1
= y [Answer]
z = xy + 6y
(dz/dy) = Partial derivative of z with respect to y
= x × y^(1 – 1) + 6y^(1 -1)
= x × y^0 + 6y^0
= x × 1 + 6 × 1
= x + 6 [Answer]
d.
z = x6y^2 + 5y^3
(dz/dx) = Partial derivative of z with respect to x
= (6y^2) × x ^(1 – 1) + 0
= (6y^2) × x ^0
= (6y^2) × 1
= 6y^2 [Answer]
z = x6y^2 + 5y^3
(dz/dy) = Partial derivative of z with respect to y
= x(6 × 2)y^(2 -1) + (5 × 3)y^(3 – 1)
= 12xy + 15y^2 [Answer]