In ∆ABC, if cot(A), cot(B) and cot(C) are in AP, then a2, b

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 Multiple Choice QuestionsMultiple Choice Questions

161.

In ABC, if 3a = b + c, then value of cotB2cotC2 will be

  • 1

  • 2

  • 3

  • 2


162.

If sin(a) and cos(a) are the roots of the equation ax2 + bx + c = 0, then

  • a2 - b2 + 2ac = 0

  • (a - c)2 = b2 + c2

  • a2 + b2 - 2ac = 0

  • a2 + b2 + 2ac = 0


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163.

In ABC, if cot(A), cot(B) and cot(C) are in AP, then a2, b2 and c2 are in

  • HP

  • AP

  • GP

  • None of the above


B.

AP

It is given, cotA, cotB and cotC are in AP.   2cotB = cotA + cotC 2cosBsinB = cosAsinA + cosCsinC    sinAa = sinBb = sinCc = k 2cosBkb = cosAak + cosCck 2cosBb = cosAa + cosCc 2ba2 + c2 - b22ac = 1ab2 + c2 - a22bc + 1ca2 + b2 - c22ab   2a2 + c2 - b22abc = 12abcb2 + c2 - a2 + a2 + b2 - c2    2a2 + c2 - b2 = 2b2                 a2 + c2 = 2b2 a2, b2 and c2 are in AP.


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164.

The maximum value of 3cosθ + 4sinθ is

  • 3

  • 4

  • 5

  • None of these


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165.

The period of sinθ - 3cosθ is

  • π4

  • π2

  • π

  • 2π


166.

If cosθ = cos2α + cos2β + cos2γsin2α + sin2β + sinγ, where α, β, γ are the angles made by a line with the positive directions of the axes of reference, then the measure of θ is

  • 60°

  • 90°

  • 30°

  • 45°


167.

If a = 2, b = 3 and c = 5in BC, then C is to equal

  • π2

  • π4

  • π6

  • None of these


168.

If f : R  R be the signum function and g : R  R be the greatest integer function, then sinπfog12 is equal to

  • 1

  • 32

  • 0

  • 12


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169.

The number of solution of tan5πcosθ = cot5πsinθ for θ in 0, 2π will be

  • 28

  • 14

  • 4

  • 2


170.

AB is a vertical pole. The end A is on the ground level. C is the middle point of AB and P is a point on the ground level. The portion BC subtends an angle β at P. If AP = nAB, then tanβ is equal to

  • n2n2 + 1

  • nn2 + 1

  • nn + 1

  • None of these


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