The slope of the curve y = excos(x), x ∈ - &p

Subject

Mathematics

Class

JEE Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

1.

If 2x + 2y = 2 then the value of dydx at (1, 1) is equal to

  • - 2

  • - 1

  • 0

  • 1


2.

Let y = tan-1secx + tanx. Then dydx is equal to

  • 14

  • 12

  • 1secx + tanx

  • 1sec2x


3.

If s = sec-112x2 - 1 and t = 1 - x2, then dsdt at x = 12 is

  • 1

  • 2

  • - 2

  • 4


4.

The minimum valuje of 2x3 - 9x2 + 12x + 4 is

  • 4

  • 5

  • 6

  • 8


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5.

The slope of the curve y = excos(x), x  - π, π is maximum at

  • x = π2

  • x = - π2

  • x = π4

  • x = 0


D.

x = 0

Let m be the slope of the tangent to the curve

y = excos(x)

Then,  m = dydx = excosx - sinx    dmdx = excosx - sinx + ex- sinx + cosx                = - 2exsinxand d2mdx2 = - 2exsinx + cosx    dmdx = 0       sinx = 0  x = 0Cleraly, d2mdx2 < 0 for x = 0


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6.

If y = f(x) is continuous on [0, 6], differentiable on (0, 6), f(0) = - 2 and f(6) = 16, then at some point between x = 0 and x = 6, f'(x) must be equal to

  • - 18

  • - 3

  • 3

  • 14


7.

The equation of tangent to the curve y = x3 - 6x + 5 at (2, 1) is

  • 6x - y - 11 = 0

  • 6x - y - 13 = 0

  • 6x + y + 11 = 0

  • 6x - y + 11 = 0


8.

Let f(x) = 2x3 - 5x2 - 4x + 3, 12  x  3. The point at which the tangent to the curve is parallel to the X-axis, is

  • (1, - 4)

  • (2, - 9)

  • (2, - 4)

  • (2, - 1)


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9.

Two sides of triangle are 8 m and 56 m in length. The angle between them is increasing at the rate 0.8=08  rad/s. When the angle between sides of fixed length is π3, the rate at which the area of the triangle is increasing, is

  • 0. 4 m2/s

  • 0.8 m2/s

  • 0 . 6 m2/s

  • 0.04 m2/s


10.

If y = 8x- 60x2 + 144x + 27 is a decreasing function in the interval

  • (- 5, 6)

  • - , 2

  • (5, 6)

  • (2, 3)


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