If f(x) = (x - 2)(x - 4)(x - 6) ... (x - 2n), then f'(2) is from

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 Multiple Choice QuestionsMultiple Choice Questions

711.

y = easin-1x  1 - x2yn + 2 - 2n + 1xyn + 1 is equal to

  • - n2 + a2yn

  • n2 - a2yn

  • n2 + a2yn

  • - n2 - a2yn


712.

The value of f(0) so that - ex + 2xx  may be continuous at x = 0 is

  • log12

  • 0

  • 4

  • - 1 + log2


713.

Let [ ] denotes the greatest integer function and f(x) = [tan2(x)] Then,

  • limx0fx does not exist

  • f(x) is continuous at x = 0

  • f(x) is not differentiable at x = 0

  • f(x) = 1


714.

If (x + y)sinu = x2y2, then xux + yuy is equal to

  • 1e

  • 12e

  • 1e2

  • 4e4


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715.

If x = 2at1 + t3 and y = 2at21 + t32, then dydx is

  • ax

  • a2x2

  • xa

  • x2a


716.

If f(x) = logx3logex2, then f'(x) at x = e is

  • 13e1 - loge2

  • 13e1 + loge2

  • 13e- 1 + loge2

  • - 13e1 + loge2


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717.

If f(x) = (x - 2)(x - 4)(x - 6) ... (x - 2n), then f'(2) is

  • (- 1)n2n - 1 (n - 1)!

  • (- 2)n - 1 (n - 1)!

  • (- 2)n n!

  • (- 1)n - 12n (n - 1)!


B.

(- 2)n - 1 (n - 1)!

 fx = x - 2x - 4x - 6 ... x - 2n

Taking log on both sides, we get

logfx = logx - 2 + logx - 4 + ... + logx - 2n

On differentiating wrt x, we get

1fxf'x = 1x - 2 + 1x - 4 + ... + 1x - 2n      f'x = x - 4x - 6 ... x- 2n + x - 2x - 6 ... x - 2n                       + ... + x - 2x - 6 ... x - 2n - 1  f'(2) = - 2- 4 ... 2 - 2n             = - 2n - 11 . 2 . ... . n - 1             = - 2n - 1 n - 1!


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718.

If fx = 1 - cosxx, x  0k,                  x = 0  is continuous at x = 0, then the value of k is

  • 0

  • 1/2

  • 14

  • 12


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719.

Let f(x)= sin(x), g(x) = x and h(x) = loge(x). If F(x) = (hogof)(x), then F"(x) is equal to

  • csc3x

  • 2cotx2 - 4x2csc2x2

  • 2xcotx2

  • - 2csc2x


720.

If y = tan-14x1 + 5x2 + tan-12 + 3x3 - 2x, then dydx is equal to

  • 51 + 25x2

  • 11 + 25x2

  • 0

  • 51 - 25x2


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