Subject

Mathematics

Class

JEE Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

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11.

Let f(x) = αxsinπx2    for x  21                      for x = 0

where αx is such that limx0αx = .

Then the function f(x) is contonuous at x = 0 if αx is chosen as

  • 2πx

  • 1x2

  • 2πx2

     

  • 1x


A.

2πx

Given,fx = αxsinπx2    for x  21                      for x = 0    ...iFor f(x)to be continuous at x = 0              limx0fx = f0From Eq (i),   f(0) = 1 For f(x)to be continuous at x = 0,limx0αxsinπx2 =1The above limlt is equal to 1, when                        αx = 2πxi.e., limx0sinπx2πx2 = 1      limx0 sinθθ = 1Hence, option  (a) αx = 2πx is correct


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12.

The points of the curve y = x3 + x - 2 at which its tangent are parallel to the straight line y = 4x - 1 are

  • (2, 7), (- 2, - 11)

  • (0, 2), (21/3, 21/3)

  • (- 21/3, - 21/3), (0, - 4)

  • (1, 0), (- 1, - 4)


13.

The equation of the normal to the curve y = - x + 2 at the point of its intersection with the bisector of the first quadrant is

  • 4x - y + 16 = 0

  • 4x - y = 16

  • 2x - y - 1 = 0

  • 2x - y + 1 = 0


14.

Let the equation ofa curve is given in implicit form as y = tanx + y. Then d2ydx2 in terms of y is

  • 21 + y2y6

  • - 21 + y2y6

  • - 21 + y2y5

  • 21 + y22y5


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15.

The angle at which the curve y = x2 and the curve x = 53cost, y = 54sint intersect is

  • tan-1241

  • tan-1412

  • - tan-1241

  • 2tan-1412


16.

The maximum value of the function y = 2tanx - tan2x over 0, π2 is

  • 1

  • 3

  • 2


17.

The function f(x) = xtan-11x for x  0, f(0) = 0 is

  • differentiable at x = 0

  • neither continuous at x = 0 nor differentiable at x = 0

  • not continuous at x = 0

  • continuous at x = 0 but not differentiable at x = 0


18.

The values of a and b for which the function y = aloge(x ) + bx2 + x, has extremum at the points x1 = 1 and x2 = 2 are

  • a = 23, b = - 16

  • a = - 23, b = - 16

  • a = - 23, b = 16

  • a = - 13, b = - 16


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19.

The tangent to the graph of a continuous function y = f(x) at the point with abscissa x = a forms with the X-axis an angle of π3 and at the point with abscissa x = b an angle of π4, then what the value of integral abf'x + f''xdx

(where f'(x) the derivative off w.r.t. xwhich is assumed to be continuous and similarly f"(x) the double derivative of f w.r.t. x)

  • eb3ea

  • eb - 3ea

  • eb - 3ea

  • - eb - 3ea


20.

A closed figure S is bounded by the hyperbola x2 - y2 = a2 and the straight line x = a + h; (h > 0, a > 0). This closed figure is rotated about the X-axis. Then, the volume of the solid ofrevolution is

  • πh23a + h

  • πh263a + h

  • πh233a + h

  • πh223a + h


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