5. Find derivative of logarithmic functions
β’ Sometimes a function is given as a
product and quotient of number of
functions in such condition we need to
logarithm of both the side of function
to differentiating it.
β’ For example
β’ π π₯ =
π₯2 6π₯+7 9
3π₯+2 7
β’ π¦ = π₯π₯
β’ π¦ = π₯ππ₯
β’ π₯π¦ = π¦π₯
β’ π¦ =
π₯
3
2 1β4π₯ 7
5βπ₯
7
2 15β8π₯
1
2
10. Derivative of parametric equations
β’ If y =f(t) and x=g(t) then
ππ¦
ππ₯
=
ππ¦
ππ‘
ππ₯
ππ‘
here t is parameter and equations are known as
parametric equations
β’ For e.g. x=ππ‘2 and y = 2ππ‘
β’ Y=π₯π₯π₯π₯π₯βββββ
β’ Y=ππππ‘ + 1 πππ π₯ = π‘ππ‘
β’ Differentiate π₯2ππ₯ π€ππ‘β ππππππ‘ π‘π log π₯
β’ Differentiate π₯ππππ₯ π€ππ‘β πππ ππππ‘ π‘π 3π₯π₯3
β’ Y= π₯ + π₯ + π₯ + π₯ + β― β¦ β¦ β¦ β¦ β¦ β¦ β¦ . . β
11. Application of derivatives :
β’ Study of derivative is important in various fields like
β’ Economics
β’ Business
β’ Psychology
β’ Many problems of trade and commerce
β’ Maximization of profit and minimization of cost and loss .
β’ To obtain marginal cost and marginal revenue
β’ To obtain elasticity of demand and supply
β’ To obtain maximum and minimum value of any function and stationary values
12. Homogeneous functions of two variables
β’ A function is called homogeneous if the degree of all the
terms are equal then only it can be represent in the form of
π = πππ
π
π
, or π = πππ
π
π
β’ A function u(x , y) is called homogeneous of degree n if u(x
, y) is expressed in the form of
β’ π = πππ
π
π
, or π = πππ
π
π
β’ For example :
π+π
π+ π
because it can be represented as π = π
π
π
π+
π
π
π+
π
π
= π
π
ππ
π
π
β’π =
π+π
π+ π
β’ =
π
(π+π)
π
π
( π+ π)
π
β’ =
π₯
π₯
π₯
+
π¦
π₯
π₯
π₯
π₯
+
π¦
π₯
=
π₯ 1+
π¦
π₯
π₯
1
2 1+
π¦
π₯
β’ =π₯1β
1
2
1+
π¦
π₯
1+
π¦
π₯
= π₯
1
2
1+
π¦
π₯
1+
π¦
π₯
=π₯
1
2 π
π¦
π₯
13. Eulerβs theorem
β’ Homogeneity of degree one is often called linear homogeneity .
β’ linear homogeneous function U=x+2y
β’ An important property of homogeneous function is given by Euler's theorem.
β’ It is developed by swiss mathematician Leonhard Euler
β’ It is mathematical relationship that applies to homogeneous function.
β’ If production function is homogeneous and one degree one and factors of production are
paid equal to marginal products (income =payment to factor (rent , wages, profit ,interest
)total product is exhausted with no surplus(profit) and deficit(loss).
β’ With the help of this theorem we can determine ,labor , capital for maximum production
14. Euler's theorem
β’ If function u(x , y) is homogeneous function of degree n then
β’ π₯
ππ’
ππ₯
+ π¦
ππ’
ππ¦
= ππ’ πππ π₯2 π2π¦
ππ₯2 + 2π₯π¦
ππ’
ππ₯ππ¦
+ π¦2 π2π₯
ππ¦2 = π π β 1 π’