Matrices and Calculus: Unit II: Differential Calculus

Chain Rule or Derivative of Composite Function

Worked Examples, Exercise problems with Answers | Differential Calculus

Worked Examples, Exercise with Answers: Chain Rule or Derivative of Composite Function: Matrices and Calculus: Differential Calculus

CHAIN RULE OR DERIVATIVE OF COMPOSITE FUNCTION

If y = f(u) and u = g(x), where f and g are differentiable, then the derivative of the composite functions is (fg)'(x) = ƒ'(g(x)) · g'(x)

In Leibnitz notation

The chain rule can be extended due to the composition of more than two functions. If y = f(u), u = g(x), x = h(t), where f, g, h are differentiable functions. 

Then y is a function of t.


In Leibnitz notation



WORKED EXAMPLES

Example 1 

Differentiate cos(x3 + 2x2 + 1) w. r. to x

Solution 

Let y = cos(x3 + 2x2 + 1) (1)



Example 2 

Find

Solution 

Let y = sin5 3x



Example 3 

Find

Solution 

Let y = log(2x2 + 3x2 + 2)



Example 4 

If y =

Solution



Example 5 


Solution




Example 6 


Solution



Example 7 


Solution



Example 8 


Solution


Instead of substitution we do it directly.


Example 9 

If f(x) = sin[cos(tan x)], then find f'(x)

Solution

Given f(x) = sin[cos(tan x)]



Example 10 


Solution



Example 11 


Solution



Example 12 

If f(x) = sin(cos2 x) cos(sin2 x), then find ƒ'(x)

Solution

Given f(x) = sin(cos2 x) cos(sin2 x)



Example 13 


Solution



Example 14 

If F(x) = f(xf(x f(x)))

where f(1) = 2, ƒ(2) = 3, ƒ'(1) = 4, ƒ'(2) = 5, ƒ'(3) = 6. Find F'(1).

Solution 

Given F(x) = F(x) = f[xf(x f(x))], f(1) = 2, ƒ(2) = 3, ƒ'(1) = 4, ƒ'(2) = 5, ƒ'(3) = 6.


Put x = 1 then


=ƒ'[3][4.5+ 2.5 + 3] = 6[33] = 198


EXERCISE 2.6

Differentiate the following functions


ANSWERS TO EXERCISE 2.6



Matrices and Calculus: Unit II: Differential Calculus : Tag: : Worked Examples, Exercise problems with Answers | Differential Calculus - Chain Rule or Derivative of Composite Function


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Matrices and Calculus

MA3151 1st semester | 2021 Regulation | 1st Semester Common to all Dept 2021 Regulation