Which of the following function is not differentiable at x = 1 ?

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 Multiple Choice QuestionsMultiple Choice Questions

701.

If fx = ax2 - b,    a  x < 12,               x = 1x + 1,       1 < x  2 Then, the value of the pair (a, b) for which f(x) cannot be continuous at x = 1, is

  • (2, 0)

  • (1, - 1)

  • (4, 2)

  • (1, 1)


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702.

Which of the following function is not differentiable at x = 1 ?

  • f(x) = tanx - 1 + x - 1

  • f(x) = sinx - 1 - x - 1

  • f(x) = x2 - 1x - 1x - 2

  • None of the above


A.

f(x) = tanx - 1 + x - 1

a fx = tanx - 1 + x - 1f'(1+) = limh0tanh + h - 0- h = 2f'(1-) = limh0tan- h + - h - 0- h = - 2

Hence, f(x) is not differentiable at x = 1

b sinx - 1 - x - 1 f'(1+) = limh0sinh - h - 0h = 0     f'(1-) = limh0sin- h - - h- h = limh0sinh - h- h = 0

Hence, f(x) is differentiable at x = 1.

(c) f(x) = (x2 - 1)x - 1x - 2

           = x + 1x - 1x - 1x - 2

which is differentiable at x = 1


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703.

Using Rolle's theorem, the equation a0xn + a1xn - 1 + ... + an = 0 has atleast one root between 0 and 1, if 

  • a0n + a1n - 1 + ... + an - 1 = 0

  • a0n - 1 + a1n - 2 + ... + an - 2 = 0

  • na0 + (n - 1)a1 + ... + an - 1 = 0

  • a0n + 1 + a1n + ... + an = 0


704.

The value of cfrom the Lagrange's mean value theorem for which f(x) = 25 - x2 in [1, 5], is

  • 5

  • 1

  • 15

  • None of these


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705.

Let f'(x), be differentiable a. If f(1) = - 2 and f'(x) 2  x [1, 6], then

  • f(6) < 8

  • f(6)  8

  • f(6)  5

  • f(6)  5


706.

If fx = 1 + sinxasinx,  - π6 < x < 0b,                                  x = 0etan2xtan3x,               0 < x < - π6

then the value of a and b, if f is continuous at x = 0, are respectively

  • 23, 32

  • 23, e23

  • 32, e32

  • None of these


707.

If f(x) = mx + 1,         x  π2sinx + n,     x > π2 is continuous at x = π2, then

  • m = 1, n = 0

  • m = 2 + 1

  • n = mπ2

  • m = n = π2


708.

If f(x) = x2,         x  02 sinx, x > 0, then x = 0 is

  • point of minima

  • point of maxima

  • point of discontinuity

  • None of the above


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709.

If y = x + y + x + y + ... , then dydx is equal to

  • y + xy2 - 2x

  • y3 - x2y2 - 2xy - 1

  • y3 + x2y2 - x

  • None of these


710.

If f : R  R is defined by

fx = 2sinx - sin2x2xcosx, if x 0a, if x = 0,           if x = 0

then the value of a so that f is continuous at 0 is

  • 2

  • 1

  • - 1

  • 0


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