The principal amplitude of sin40° + icos40°

Subject

Mathematics

Class

JEE Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

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1.

The principal amplitude of sin40° + icos40°5 is

  • 70°

  • - 110°

  • 110°

  • - 70°


B.

- 110°

We have, sin40° + icos40°5= i5cos40° - isin40°5= i5cos200° - isin200°        by De-Moiver's Theorem= icos270° - 70° - isin270° - 70°= i- sin70° + icos70°= i- sin180° - 110° + icos180° - 110°= i- sin110° - icos110° Principal amplitude of sin40° + icos40°5 is - 110°


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2.

If fx = x - 1x + 1, then f(2x) is

  • fx + 1fx + 3

  • 3fx + 1fx + 3

  • fx + 3fx + 1

  • fx + 33fx + 1


3.

If the distance between the plane Ax - 2 y + z = d and the plane containing the lines x - 12 = y - 23 = z - 34 and x - 23 = y - 34 = z - 45 is 6, then d is equal to

  • 3

  • 4

  • 6

  • 1


4.

If the lines x - 12 = y + 23 = z - 14 and x - 31 = y - k2 = z1 intersect, then the value of k is

  • 3/2

  • 7/2

  • - 2/7

  • - 3/2


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5.

If A = {x : x2 - 5x + 6 = 0}, B={2, 4}, C = {4, 5}, then A x (B ∩ C) is

  • {(2, 4), (3, 4)}


  • {(4, 2), (4, 3)}

  • {(2, 4), (3, 4), (4, 4)}

  • {(2, 2), (3, 3), (4, 4), (5, 5)}


6.

Let A and B be two non-empty sets having n elements in common. Then, the number of elements common to A x B and B x A is

  • 2n

  • n

  • n2

  • None of these


7.

∼ (P ∨ q) v ( ∼ p ∧ q) is logically equivalent to

  • - p

  • p

  • q


8.

The foci of a hyperbola are (- 5, 18) and (10, 20) and it touches the Y-axis. The length of its transverse axis is

  • 100

  • 892

  • 89

  • 50


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9.

The locus of mid-point of the line segment joining the locus to a moving point on the parabola y2 = 4ax is another parabola with directrix

  • x = - a

  • x = a

  • x = 0

  • x = a/2


10.

The equation of the ellipse with its centre at (1, 2), one locus at (6, 2) and passing through (4, 6) is

  • x - 1245 + y - 2220 = 1

  • x - 1220 + y - 2245 = 1

  • x + 1245 + y + 2220 = 1

  • None of the above


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