Home
Class 12
MATHS
Number of points where f (x)= {{:(max(|x...

Number of points where `f (x)= {{:(max(|x ^(2)- x-2","x ^(2) -3x),,, x ge0),( max (ln (-x)"," e ^(x)),,, x lt 0):}` is non-differentiable will be:

A

1

B

2

C

3

D

None of these

Text Solution

AI Generated Solution

The correct Answer is:
To determine the number of points where the function \[ f(x) = \begin{cases} \max(|x^2 - x - 2|, x^2 - 3x) & \text{for } x \geq 0 \\ \max(\ln(-x), e^x) & \text{for } x < 0 \end{cases} \] is non-differentiable, we will analyze each case separately. ### Step 1: Analyze \( f(x) \) for \( x \geq 0 \) For \( x \geq 0 \), we need to consider the two functions \( |x^2 - x - 2| \) and \( x^2 - 3x \). 1. **Find the roots of \( x^2 - x - 2 \)**: \[ x^2 - x - 2 = 0 \implies (x - 2)(x + 1) = 0 \implies x = 2, -1 \] Since we are only interested in \( x \geq 0 \), we take \( x = 2 \). 2. **Evaluate \( |x^2 - x - 2| \)**: - For \( 0 \leq x < 2 \), \( x^2 - x - 2 < 0 \) so \( |x^2 - x - 2| = -(x^2 - x - 2) = -x^2 + x + 2 \). - For \( x = 2 \), \( |x^2 - x - 2| = 0 \). - For \( x > 2 \), \( x^2 - x - 2 \geq 0 \) so \( |x^2 - x - 2| = x^2 - x - 2 \). 3. **Find the roots of \( x^2 - 3x \)**: \[ x^2 - 3x = 0 \implies x(x - 3) = 0 \implies x = 0, 3 \] ### Step 2: Determine the intervals for \( f(x) \) - For \( 0 \leq x < 2 \): \[ f(x) = \max(-x^2 + x + 2, x^2 - 3x) \] Evaluate at \( x = 0 \): \[ f(0) = \max(2, 0) = 2 \] Evaluate at \( x = 1 \): \[ f(1) = \max(2, -2) = 2 \] Evaluate at \( x = 2 \): \[ f(2) = \max(0, -2) = 0 \] - For \( 2 < x < 3 \): \[ f(x) = \max(x^2 - x - 2, x^2 - 3x) = x^2 - 3x \] - For \( x \geq 3 \): \[ f(x) = x^2 - x - 2 \] ### Step 3: Points of non-differentiability for \( x \geq 0 \) 1. **At \( x = 0 \)**: - \( f(x) \) changes from \( 2 \) to \( 0 \) (discontinuity). 2. **At \( x = 2 \)**: - The function transitions from \( -x^2 + x + 2 \) to \( x^2 - 3x \) (abrupt change). 3. **At \( x = 3 \)**: - The function transitions from \( x^2 - 3x \) to \( x^2 - x - 2 \) (abrupt change). ### Step 4: Analyze \( f(x) \) for \( x < 0 \) For \( x < 0 \): - \( f(x) = \max(\ln(-x), e^x) \) 1. **Evaluate at \( x = -1 \)**: \[ f(-1) = \max(\ln(1), e^{-1}) = \max(0, \frac{1}{e}) = \frac{1}{e} \] 2. **Behavior as \( x \to 0^- \)**: - \( \ln(-x) \to -\infty \) and \( e^x \to 1 \), hence \( f(x) \to 1 \). ### Step 5: Points of non-differentiability for \( x < 0 \) - At \( x = 0 \): The function is not defined (discontinuity). - The function \( \ln(-x) \) and \( e^x \) are both continuous, but their maximum function may have a point of non-differentiability depending on their slopes. ### Conclusion The total points of non-differentiability are: - \( x = 0 \) (discontinuity) - \( x = 2 \) (abrupt change) - \( x = 3 \) (abrupt change) Thus, the number of points where \( f(x) \) is non-differentiable is **3**. ### Final Answer: The number of points where \( f(x) \) is non-differentiable is **3**. ---
Promotional Banner

Topper's Solved these Questions

  • CONTINUITY, DIFFERENTIABILITY AND DIFFERENTIATION

    VIKAS GUPTA (BLACK BOOK)|Exercise EXERCISE (ONE OR MORE THAN ONE ANSWER IS/ARE CORRECT)|36 Videos
  • CONTINUITY, DIFFERENTIABILITY AND DIFFERENTIATION

    VIKAS GUPTA (BLACK BOOK)|Exercise EXERCISE (COMPREHENSION TYPE PROBLEMS)|32 Videos
  • COMPOUND ANGLES

    VIKAS GUPTA (BLACK BOOK)|Exercise Exercise-5 : Subjective Type Problems|31 Videos
  • DETERMINANTS

    VIKAS GUPTA (BLACK BOOK)|Exercise EXERCISE-4 : SUBJECTIVE TYPE PROBLEMS|12 Videos

Similar Questions

Explore conceptually related problems

Let f (x) = {{:(min (x"," x ^(2)), x ge 0),( max (2x "," x-1), x lt 0):}, then which of the following is not true ?

If f(x) = {{:(x - 3",",x lt 0),(x^(2) - 3x + 2",",x ge 0):} , then g(x) = f(|x|) is

Let f(x) = {{:(( 2+x)",",if , x ge0), (( 2-x)",", if , x lt 0):} show that f(x) not derivable at x =0

If f(x) = {(x,",", x ge 0),(x^(2),",",x lt 0):} , then f(x) is

Let f (x)= max (x,x ^(2) x ^(3)) in -2 le x le 2. Then:

If f(x) = {{:(x - 3",",x lt 0),(x^(2)-3x + 2",",x ge 0):}"and let" g(x) = f(|x|) + |f(x)| . Discuss the differentiability of g(x).

If f(x)=max{x^(2)-4,|x-2|,|x-4|} then:

Find k, if possible, so that f (x)= [{:((ln (2- cos 2x))/(ln ^(2) (1+ sin 3x)),,, x lt 0),(k,,, x=0),((e ^(sin 2x )-1)/(ln (1+ tan 9x)),,, x gt 0):} is continious at x=0.

VIKAS GUPTA (BLACK BOOK)-CONTINUITY, DIFFERENTIABILITY AND DIFFERENTIATION-EXERCISE (SUBJECTIVE TYPE PROBLEMS)
  1. Number of points where f (x)= {{:(max(|x ^(2)- x-2","x ^(2) -3x),,, x ...

    Text Solution

    |

  2. Let f (x)= {{:(ac (x-1)+b,,, x lt 1),( x+2,,, 1 le x le 3),(px ^(2) +q...

    Text Solution

    |

  3. If y= sin (8 sin ^(-1) x ) then (1-x ^(2)) (d^(2)y)/(dx ^(2))-x (dy)/...

    Text Solution

    |

  4. If y ^(2) =4ax, then (d^(2) y)/(dx ^(2))=(ka ^(2))/( y ^(3)), where k ...

    Text Solution

    |

  5. The number of values of x , x I [-2,3] where f (x) =[x ^(2)] sin (pix)...

    Text Solution

    |

  6. If f (x) is continous and fifferentiable in [-3,9] and f'(x) in [-2,8]...

    Text Solution

    |

  7. In f (x)= [{:(cos x ^(3),, x lt 0), ( sin x ^(3) -|x ^(3)-1|,, x ge 0)...

    Text Solution

    |

  8. Let f (x) =x ^(2) +ax+3 and g (x) =x+b, where F (x) =lim (xto oo) (f(x...

    Text Solution

    |

  9. Let f (x)= {{:(2-x"," , -3 le x le 0),( x-2"," , 0 lt x lt 4):} Then f...

    Text Solution

    |

  10. If f (x) +2 f (1-x)( =x ^(2) +2AA x in R and f (x) is a differentiable...

    Text Solution

    |

  11. Let f (x)= signum (x) and g (x) =x (x ^(2) -10x+21), then the number o...

    Text Solution

    |

  12. If (d^(2))/(d x ^(2))((sin ^(4)x+ sin ^(2)x+1)/(sin ^(2)x + si n x+1))...

    Text Solution

    |

  13. f (x) =a cos (piy)+b, f'((1)/(2))=pi and int (1//2)^(3//2) f (x) dx =2...

    Text Solution

    |

  14. Let alpha (x) = f(x) -f (2x) and beta (x) =f (x) -f (4x) and alpha '(1...

    Text Solution

    |

  15. Let f (x) =-4.e ^((1-x)/(2))+ (x ^(3))/(3 ) + (x ^(2))/(2)+ x+1 and g ...

    Text Solution

    |

  16. If y=e^(2 sin ^(-1)x) then |((x ^(2) -1) y ^('') +xy')/(y)| is equal t...

    Text Solution

    |

  17. Let f (x)=x+ (x ^(2))/(2 )+ (x ^(3))/(3 )+ (x ^(4))/(4 ) +(x ^(5))/(5)...

    Text Solution

    |

  18. In f (x)= [{:(cos x ^(2),, x lt 0), ( sin x ^(3) -|x ^(3)-1|,, x ge 0)...

    Text Solution

    |

  19. Let f :R to R be a differentiable function satisfying: f (xy) =(f(x)...

    Text Solution

    |

  20. For the curve sinx+siny=1 lying in first quadrant. If underset(xrarr0...

    Text Solution

    |

  21. Let f (x) = x tan ^(-1) (x^(2)) + x^(4) Let f ^(k) (x) denotes k ^(th)...

    Text Solution

    |