Let f(x) = - 2sinx      &

Subject

Mathematics

Class

JEE Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

1.

The system 1- 1235- 326axyz = 3b2 has no solutions, if

  • a = - 5, b  5

  • a = - 5, b = 5

  • a  - 5, b = 5

  • a  - 5, b  5


2.

The equation of displacement of a particle is x(t) = 5t2 - 7t + 3. The acceleration at the moment when its velocity becomes 5 m/sec is

  • 3 m/sec2

  • 7 m/sec2

  • 10 m/sec2

  • 8 m/sec2


3.

The range of x for which the formula 3sin-1x = sin-1x3 - 4x2 hold is

  • - 12  x  12

  • - 14  x  23

  • - 13  x  1

  • - 23  x  23


4.

The mean value of the function fx = 2ex + 1 on the interval [0, 2] is

  • 2 - loge2e2 + 1

  • 2 + loge2e2 + 1

  • 2 + loge2e2 - 1

  • - 2 + loge2e2 - 1


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5.

If 72 and 1 are the roots of the equation 2x3722x2762x = 0, then third root is

  • - 72

  • - 92

  • - 32

  • - 52


6.

The function y = 2x - x2

  • increases in (0, 1) but decreases in (1, 2)

  • decreases in (0, 2)

  • increases m (1, 2) but decreases in (0, 1)

  • increases in (0, 2)


7.

The interval in which the function y = x - 2sinx0  x  2π increases throughout is

  • 5π3, 2π

  • 0, π3

  • π3, 5π3

  • 0, π4


8.

The inverse ofthe function y = 2x1 + 2x is

  • x = log211 - 2y

  • x = log21 - 1y

  • x = log211 - y

  • x = log2y1 - y


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9.

The domain of the definition of the function

y = 1log101 - x + x +2 is

  • x  - 2

  • - 3 < x  - 2

  • - 2  x < 0

  • - 2  x < 1


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10.

Let f(x) = - 2sinx            if x  - π2Asinx + B if - π2 < x < π2cosx                 if x  π2

For what values of A and B, the function f(x) is continuous throughout the real line ?

  • A = - 1, B = 1

  • A = - 1, B = - 1

  • A = 1, B = - 1

  • A = 1, B = 1


A.

A = - 1, B = 1

Given,fx = - 2sinx            if x  - π2Asinx + B if - π2 < x < π2cosx                 if x  π2       ...i

From above conditions function f(x) is continuous throughout the real line, when function f(x) is continuous at x = - π2 and π2

For continuity at x = - π2

limxπ-2fx = limxπ+2fx = f- π2      ...iilimxπ-2fx = 2  limxπ+2fx= - A + B   f- π2 = 2 From Eq. (ii), we get - A +B = 2                                   ...iiiFor continuity at x = π2         limxπ-2fx = limxπ+2fx  = fπ2      ...ivHere, limxπ-2fx = A + B  limxπ+2fx = 0And          fπ2 = 0 From Eq. (iv)A + B = 0 From Eqs (iii) and (v)         A = - 1, B = 1


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