Continuity and Differentiability

Get insights from 335 questions on Continuity and Differentiability, answered by students, alumni, and experts. You may also ask and answer any question you like about Continuity and Differentiability

Follow Ask Question
335

Questions

0

Discussions

0

Active Users

0

Followers

New answer posted

a year ago

0 Follower 5 Views

A
alok kumar singh

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Sol:

G i v e n     t h a t                     f ( x ) = l o g ( x 2 + 2 ) − l o g 3     i n     [ − 1 , 1 ] (i)  f(x)=log(x2+2)−log3,  being  a  logarithm  functions,  f(x)  is  continuous  in  [−1,1]. ( i i )               f ' ( x ) = 1 x 2 + 2 . 2 x − 0 = 2 x x 2 + 2     w h i c h     e x i s t s     i n     ( − 1 , 1 ) S o     f ( x )     i s     d i f f e r e n t i a b l e     i n     ( − 1 , 1 ) . ( i i i )               f ( − 1 ) = l o g ( 1 + 2 ) − l o g 3                 ⇒ l o g 3 − l o g 3 = 0                                       f ( 1 ) = l o g ( 1 + 2 ) − l o g 3                 ⇒ l o g 3 − l o g 3 = 0 ∴                           f ( − 1 ) = f ( 1 ) = 0 As  the  above  conditions  are  satisfied,  then  there  must  exist  at  least  one  point c∈(−1,1)  such  that  f'(c)=0 ∴     2 c c 2 + 2 = 0                 ⇒ 2 c = 0                 ⇒ c = 0 ∈ ( − 1 , 1 ) H e n c e ,     R o l l e ' s     T h e o r e m     i s     v e r i f i e d .

New answer posted

a year ago

0 Follower 5 Views

A
alok kumar singh

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Sol:

G i v e n     t h a t                     f ( x ) = s i n 4 x + c o s 4 x     i n     [ 0 , π 2 ] (i)  f(x)=sin4x+cos4x,  being  sine  and  cosine  functions,  f(x)  is  continuous  in  [0,π2]. ( i i )               f ' ( x ) = 4 s i n 3 x . c o s x + 4 c o s 3 x ( − s i n x )                                                       = 4 s i n 3 x . c o s x − 4 s i n x c o s 3 x                                                       = 4 s i n x . c o s x ( s i n 2 x − c o s 2 x )                                                       = − 4 s i n x . c o s x ( c o s 2 x − s i n 2 x )                                                       = − 2 . 2 s i n x . c o s x c o s 2 x                                           [ ? c o s 2 x = c o s 2 x − s i n 2 x             s i n 2 x = 2 s i n x c o s x ]                                                       = − 2 s i n 2 x . c o s 2 x = − s i n 4 x     w h i c h     e x i s t s     i n     ( 0 , π 2 ) S o     f ( x )     i s     d i f f e r e n t i a b l e     i n     ( 0 , π 2 ) . ( i i i )               f ( 0 ) = s i n 4 ( 0 ) + c o s 4 ( 0 ) = 1                         f ( π 2 ) = s i n 4 ( π 2 ) + c o s 4 ( π 2 ) = 1 ∴                           f ( 0 ) = f ( π 2 ) = 1 As  the  above  conditions  are  satisfied,  then  there  must  exist  at  least  one  point c∈(0,π2)  such  that  f'(c)=0 ∴     f ' ( c ) = 0                 ⇒ − s i n 4 c = 0                 ⇒ s i n 4 c = 0 ⇒   s i n 4 c = s i n 0   ⇒ 4 c = n π ∴                             c = n π 4 ,     n ∈ I F o r     n = 1 ,                           c = π 4 ∈ ( 0 , π 2 ) H e n c e ,     R o l l e ' s     T h e o r e m     i s     v e r i f i e d .

New answer posted

a year ago

0 Follower 14 Views

A
alok kumar singh

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Sol:

G i v e n     t h a t                     f ( x ) = x ( x − 1 ) 2     i n     [ 0 , 1 ] (i)  f(x)=x(x−1)2,  being  an  algebraic  polynomial,  is  continuous  in  [0,1]. ( i i )               f ' ( x ) = x . 2 ( x − 1 ) + ( x − 1 ) 2 . 1                                                       = 2 x 2 − 2 x + x 2 + 1 − 2 x                                                       = 3 x 2 − 4 x + 1     w h i c h     e x i s t s     i n     ( 0 , 1 ) ( i i i )               f ( x ) = x ( x − 1 ) 2                                                       = 0 ( 0 − 1 ) 2 = 0 ;     f ( 1 ) = 1 ( 1 − 1 ) 2 = 0 ⇒                     f ( 0 ) = f ( 1 ) = 0 As  the  above  conditions  are  satisfied,  then  there  must  exist  at  least  one  point c∈(0,1)  such  that  f'(c)=0 ∴     f ' ( c ) = 3 c 2 − 4 c + 1 = 0     ⇒ 3 c 2 − 3 c − c + 1 = 0 ⇒     3 c ( c − 1 ) − 1 ( c − 1 ) = 0     ⇒ ( c − 1 ) ( 3 c − 1 ) = 0                                         c − 1 = 0           ⇒ c = 1                                         3 c − 1 = 0           ⇒ 3 c = 1           ∴ c = 1 3 ∈ ( 0 , 1 ) H e n c e ,     R o l l e ' s     T h e o r e m     i s     v e r i f i e d .

New answer posted

a year ago

0 Follower 5 Views

A
alok kumar singh

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Sol:

G i v e n     t h a t                     y = t a n − 1 x ⇒                                                         x = t a n y D i f f e r e n t i a t i n g     b o t h     s i d e s     w . r . t .     y ⇒            dxdy=sec2y⇒       dydx=1sec2y=cos2y A g a i n     d i f f e r e n t i a t i n g     b o t h     s i d e s     w . r . t .     x ⇒                               d d x ( d y d x ) = d d x ( cos2y ) ⇒                               d 2 y d x 2 = 2 c o s y ( − s i n y ) . d y d x ⇒               d2ydx2=−2sinycosy.cos2y ∴                  d2ydx2=−2sinycos3y

New answer posted

a year ago

0 Follower 4 Views

A
alok kumar singh

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Sol:

New answer posted

a year ago

0 Follower 5 Views

A
alok kumar singh

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Sol:

New answer posted

a year ago

0 Follower 5 Views

A
alok kumar singh

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Sol:

G i v e n     t h a t                     y = ( c o s x ) ( c o s x ) ( c o s x ) … ∞ ⇒                                                           y = ( c o s x ) y                                               [ ? y = ( c o s x ) ( c o s x ) ( c o s x ) … ∞ ] T a k i n g     l o g     o n     b o t h     t h e     s i d e s ,     l o g y = y . l o g ( c o s x ) D i f f e r e n t i a t i n g     b o t h     s i d e s     w . r . t .     x                     1 y . d y d x = y . d d x l o g ( c o s x ) + l o g ( c o s x ) . d y d x ⇒             1 y . d y d x = y . 1 c o s x . d d x ( c o s x ) + l o g ( c o s x ) . d y d x ⇒             1 y . d y d x = y . 1 c o s x . ( − s i n x ) + l o g ( c o s x ) . d y d x ⇒             1 y . d y d x − l o g ( c o s x ) . d y d x = − y t a n x ⇒             [ 1 y − l o g ( c o s x ) ] d y d x = − y t a n x ⇒                                                                                       d y d x = − y t a n x 1 y − l o g ( c o s x ) = y 2 t a n x y l o g c o s x − 1 H e n c e ,         d y d x = y 2 t a n x y l o g c o s x − 1 H e n c e ,     p r o v e d .

New answer posted

a year ago

0 Follower 3 Views

A
alok kumar singh

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Sol:

G i v e n     t h a t                     y x = e y − x T a k i n g     l o g     o n     b o t h     t h e     s i d e s ,                             l o g y x = l o g e y − x ⇒                   x l o g y = ( y − x ) l o g e                 ⇒ x l o g y = y − x                 [ ? l o g e = 1 ] ⇒                   x l o g y + x = y ⇒                   x ( l o g y + 1 ) = y ⇒                   x = y l o g y + 1 D i f f e r e n t i a t i n g     b o t h     s i d e s     w . r . t .     y                     d x d y = d d y ( y l o g y + 1 ) ⇒                                       = ( l o g y + 1 ) . 1 − y . d d y ( l o g y + 1 ) ( l o g y + 1 ) 2 ⇒                                         = ( l o g y + 1 ) − y . 1 y ( l o g y + 1 ) 2 = l o g y + 1 − 1 ( l o g y + 1 ) 2 = l o g y ( l o g y + 1 ) 2 W e     k n o w     t h a t     H e n c e ,         d y d x = 1 d x d y = 1 l o g y ( l o g y + 1 ) 2 = ( l o g y + 1 ) 2 l o g y H e n c e ,     p r o v e d .

New answer posted

a year ago

0 Follower 5 Views

A
alok kumar singh

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Sol:

G i v e n     t h a t                     x = e x y T a k i n g     l o g     o n     b o t h     t h e     s i d e s ,                             l o g x = l o g e x y ⇒                   l o g x = x y l o g e                 ⇒ l o g x = x y                 [ ? l o g e = 1 ]                                     … ( 1 ) D i f f e r e n t i a t i n g     b o t h     s i d e s     w . r . t .     x                     d d x l o g x = d d x ( x y ) ⇒                                       1 x = y . 1 − x . d y d x y 2 ⇒ y 2 = x ( y − x . d y d x ) ⇒                                   y 2 = x y − x 2 . d y d x           ⇒ − x 2 . d y d x = y 2 − x y ⇒                                   d y d x = y 2 − x y − x 2 = − y 2 + x y x 2 = y ( x − y ) x 2 ⇒                                   d y d x = y x . ( x − y ) x = 1 l o g x . ( x − y x )                     [ ?     l o g x = x y     f r o m     e q n ( 1 ) ] H e n c e ,         d y d x = x − y x l o g x .         H e n c e ,     p r o v e d .

New answer posted

a year ago

0 Follower 6 Views

A
alok kumar singh

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Sol:

G i v e n     t h a t                     a x 2 + 2 h x y + b y 2 + 2 g x + 2 f y + c = 0 D i f f e r e n t i a t i n g     b o t h     s i d e s     w . r . t .     x                     d d x ( a x 2 + 2 h x y + b y 2 + 2 g x + 2 f y + c ) = d d x ( 0 ) ⇒           a . 2 x + 2 h ( x . d y d x + y . 1 ) + b . 2 y . d y d x + 2 g . 1 + 2 f . d y d x + 0 = 0 ⇒           2 a x + 2 h x . d y d x + 2 h y + 2 b y . d y d x + 2 g + 2 f . d y d x = 0 ⇒         2 h x . d y d x + 2 b y . d y d x + 2 f . d y d x = − 2 a x − 2 h y − 2 g ⇒           ( 2 h x + 2 b y + 2 f ) . d y d x = − 2 ( a x + h y + g ) ⇒           d y d x = − 2 ( a x + h y + g ) 2 ( h x + b y + f ) = − ( a x + h y + g ) ( h x + b y + f ) ⇒           d y d x = − ( a x + h y + g ) ( h x + b y + f ) N o w ,     d i f f e r e n t i a t i n g     b o t h     s i d e s     w . r . t .     y                     d d y ( a x 2 + 2 h x y + b y 2 + 2 g x + 2 f y + c ) = d d y ( 0 ) ⇒           2 a x . d x d y + 2 h ( y . d x d y + x . 1 ) + 2 b y + 2 g . d x d y + 2 f . 1 + 0 = 0 ⇒           2 a x . d x d y + 2 h y . d x d y + 2 h x + 2 b y + 2 g . d x d y + 2 f = 0 ⇒           2 a x d x d y + 2 h y . d x d y + 2 g . d x d y = − 2 h x − 2 b y − 2 f ⇒           ( 2 a x + 2 h y + 2 g ) . d x d y = − 2 ( h x + b y + f ) ⇒           d x d y = − 2 ( h x + b y + f ) 2 ( a x + h y + g ) = − ( h x + b y + f ) ( a x + h y + g ) ⇒             d x d y = − ( h x + b y + f ) ( a x + h y + g ) ∴ d y d x . d x d y = [ − ( a x + h y + g ) ( h x + b y + f ) ] . [ − ( h x + b y + f ) ( a x + h y + g ) ] = 1 H e n c e ,         d y d x . d x d y = 1 .         H e n c e ,     p r o v e d .

Get authentic answers from experts, students and alumni that you won't find anywhere else

Sign Up on Shiksha

On Shiksha, get access to

  • 67k Colleges
  • 1.2k Exams
  • 718k Reviews
  • 1850k Answers

Share Your College Life Experience

×

This website uses Cookies and related technologies for the site to function correctly and securely, improve & personalise your browsing experience, analyse traffic, and support our marketing efforts and serve the Core Purpose. By continuing to browse the site, you agree to Privacy Policy and Cookie Policy.