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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

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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 for \( x \geq 0 \) 1. **Identify the functions**: - \( g_1(x) = |x^2 - x - 2| \) - \( g_2(x) = x^2 - 3x \) 2. **Find the points where \( g_1(x) \) changes**: - Set \( x^2 - x - 2 = 0 \): \[ (x - 2)(x + 1) = 0 \implies x = 2 \text{ or } x = -1 \] - Since we are considering \( x \geq 0 \), we only take \( x = 2 \). 3. **Evaluate \( g_1(x) \) and \( g_2(x) \) at critical points**: - For \( x = 0 \): \[ g_1(0) = |0^2 - 0 - 2| = 2, \quad g_2(0) = 0^2 - 3 \cdot 0 = 0 \implies f(0) = \max(2, 0) = 2 \] - For \( x = 2 \): \[ g_1(2) = |2^2 - 2 - 2| = |0| = 0, \quad g_2(2) = 2^2 - 3 \cdot 2 = -2 \implies f(2) = \max(0, -2) = 0 \] - For \( x = 3 \): \[ g_1(3) = |3^2 - 3 - 2| = |4| = 4, \quad g_2(3) = 3^2 - 3 \cdot 3 = 0 \implies f(3) = \max(4, 0) = 4 \] 4. **Check for non-differentiability**: - At \( x = 2 \), \( g_1(x) \) changes from \( g_1(x) = -(x^2 - x - 2) \) to \( g_1(x) = x^2 - x - 2 \). - The derivatives from the left and right at \( x = 2 \) will differ, indicating non-differentiability. ### Step 2: Analyze for \( x < 0 \) 1. **Identify the functions**: - \( h_1(x) = \ln(-x) \) - \( h_2(x) = e^x \) 2. **Find the point where \( h_1(x) \) changes**: - The function \( \ln(-x) \) is defined for \( x < 0 \) and is continuous and differentiable in this interval. - The function \( e^x \) is also continuous and differentiable for all \( x \). 3. **Check at \( x = -1 \)**: - At \( x = -1 \): \[ h_1(-1) = \ln(1) = 0, \quad h_2(-1) = e^{-1} \approx 0.367879 \implies f(-1) = \max(0, 0.367879) = 0.367879 \] - As \( x \) approaches \( -1 \) from the left, \( \ln(-x) \) approaches \( 0 \) and \( e^x \) approaches \( 0.367879 \). 4. **Check for non-differentiability**: - At \( x = -1 \), the derivatives of \( h_1(x) \) and \( h_2(x) \) will differ, indicating non-differentiability. ### Conclusion The function \( f(x) \) is non-differentiable at the following points: - \( x = 0 \) (discontinuity) - \( x = 2 \) (sharp point) - \( x = -1 \) (sharp point) Thus, the total number of points where \( f(x) \) is non-differentiable is **3**.
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VIKAS GUPTA (BLACK BOOK) ENGLISH-CONTINUITY, DIFFERENTIABILITY AND DIFFERENTIATION-EXERCISE (SUBJECTIVE TYPE PROBLEMS)
  1. Number of points where f (x)= {{:(max(|x ^(2)- x-2|","x ^(2) -3x),,, x...

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

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

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

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

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

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

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  8. Consider f(x) =x^(2)+ax+3 and g(x) =x+band F(x) = lim( n to oo) (f...

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

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

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

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

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

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

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

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

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  17. Let f be continuous function on [0,oo) such that lim (x to oo) (f(x)+ ...

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

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

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

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

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