Cbse Class11 Maths Notes 13 Limits And Derivatives 4h4et

Chapter 13 LIMITS AND DERIVATIVES Some standard results on limits

( )

1)

( )

iff

2)

( )

where k is a fixed real number. ( )

3)

( )

where f(x) is a real polynomial in x. for all n  N

4) 5)

x

c

Algebra of limits Refer : NCERT Textbook page no: 292.

Evaluation of algebraic limits Type I ( Direct substitution method) Eg:

(

Evaluate

) = 13 – 12 + 1 = 1

Evaluate the following limits: NCERT Textbook Exercise 13.1 Q 1,2,3,4,5,9,11,12. Additional Questions and HOT Questions

** 1)

(

** 2)

( √

** 3)

)

Ans: 1

) 60

Ans: 1

√

Ans:2

Type II (Factorisation method) Eg : Evaluate : ( form)

(

= =

)(

)

(

= 12 + 1 + 1 = 3

)

Evaluate the following limits. NCERT Textbook Exercise 13.1 Q 7,8 , Example 2. Evaluate: (

** 1) ** 2)

)(√

)

ans: ans:

√

2

** 3) Type III

ans: 0

For any positive integer n,

=

( This is applicable

for any rational number n and for a Evaluate : Ans:

=

= 4

= 4

= 32

Evaluate the following limits. NCERT Textbook Exercise 13.1 Q 10 , Example 3. 1)

Evaluate :

2)

If

Ans: 64 = 9 , find the value of a.

Type IV √

Evaluate √

Ans:

√

=

Put y = 1+x when x value =

√

⁄

= =

0, y

⁄

1

Evaluate 1)

NCERT Ex 13.1 Q 6

2)

3)

4)

(

)

(

)

(

)

(

) ⁄

ans = – n ans =

ans =

Type V Concepts :

=1 =1 =1

NCERT Exercise 13.1 : Q 13, 14, 16, 18, 19, 20, 21 Evaluate :

ans:

Evaluate :

ans:

Type VI NCERT Exercise 13.1 : Q 17 Evaluate :

Type VII Evaluate :

(

)

(

)

(

)

(

)

Let

=

=

, ,

(

)-

(

)-

=

Textbook Q no: 22 ans: 2

Evaluate 1)

2)

ans :

3)

ans : (–1)

4)

(

ans : ½

)2

Type VIII Applying sin C  sin D formulae Evaluate 1)

ans : cos a

2)

Type IX ( )

( )

** NCERT Exercise 13.1 1) Q 23 2) Q 24 3) Q 25 4) Q 26 |

** 5) If ( )

6) If ( )

|

{

{

( )

, find

, find

( )

Type X ** NCERT Exercise 13.1 -

1) Q 28 2) Q 30 3) Q 32 4) Let ( )

{

. Find k if

( ) exists. Ans : k = –1

Type XI Exponential Limits =

1

NCERT Exercise 13.2

Q1 , Q2, Q4, Q6.

Type XII NCERT Exercise 13.2

Q3 , Q5

Type XIII (

)

=1

NCERT Exercise 13.2

Q7 , Q8

DIFFERENTIATION Type I Find the derivatives of the following functions from first principle. 1) 2) 3) 4) (

)

5) 6) NCERT Ex 13.2 Q4 ** 7) sin x ** 8) cos x

** 9) tan x ** 10) sec x ** 11) cosec x ** 12) sin 2x ** 13) cos 3x 14) x sin x 15) sin2 x 16) sin(x+1) 17) Misc Example 19

Type II Find the derivatives of the following * 1) 2) 3)

4) 5) * 6)

Type III Ex 13.2 Q1 Ex 13.2 Q2 Ex 13.2 Q3 Ex 13.2 Q5

Type IV (

)= .

+ .

NCERT Ex 13.2 * 1) Q7 (1),(2) * 2) Q9 (2) ,(3), (4),(5) * 3) Q11 (1) * 4) Example 18 ** 5) Misc Ex Q 15, Q22, Q25, Q29.

Type V –

( )=

Misc Exercise Q 5,6,7,8,9,16,17,18,20,26.

Additional questions and HOT Questions 1. Find the derivatives of the following functions a) ** b) (

)(

)

** c)

2. If

show that

= y.