If the axes are rotated through an angle 45° in the positive

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181.

If the axes are rotated through an angle 45° in the positive direction without changing the origin,then the co-ordinates of the point (2, 4) in the old system are

  • 1 - 22, 1 + 22

  • 1 + 22, 1 - 22

  • 22, 2

  • 2, 2


A.

1 - 22, 1 + 22

If θ he angle of rotation, then the co-ordinates in the new system are x' = xcosθ + ysinθy' = ycosθ - xsinθ.

Given that, x' = 2, y' = 4Thus, xcosθ + ysinθ = 2ycosθ - xsinθ = 4Also, θ = π4  xcosπ4 + ysinπ4 = 2and cosπ4 - xsinπ4 = 4   x + y = 2           ...iand y - x = 42      ...iiOn adding Eqs. (i) and (ii), we get 2y = 2 + 42 y = 1 +22On subtracting (i) and (ii), we get    2x = 2 - 42 x = 1 - 22Thus, the co-ordinates of 2, 4 in the old system1 - 22, 1 + 22


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182.
  • x2y2/3 + (xy2)23 = 1

  • x2 - y2 = 4xy

  • x2 - y2 = 12xy

  • x2 - y22 = 16xy


183.

fx = cos2x + sin4xsin2x + cos4x, for x  R, then f(2002) is equal to

  • 1

  • 2

  • 3

  • 4


184.

The function f : R  R is defined by f(x) = cos2x + sin4x for x  R, then f(R) is equal to

  • (34, 1]

  • [34, 1)

  • 34, 1

  • 34, 1


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185.

If xn = cosπ4n + isinπ4n, then x1, x2, x3... is equal to

  • 1 + i32

  • - 1 + i32

  • 1 - i32

  • - 1 - i32


186.

If z = 3 + 5i, then z3 + z¯ + 198 is equal to

  • - 3 - 5i

  • - 3 + 5i

  • 3 - 5i

  • 3 + 5i


187.

If fx = sin2π8 + x2 - sin2π8 - x2, then the period of f is

  • π3

  • π2

  • π

  • 2π


188.
  • 5633

  • 3356

  • 1665

  • 6061


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189.

k = 13 cos22k - 1π12 is equal to

  • 0

  • 12

  • - 12

  • 32


190.

If 3 + 2isinθ1 - 2isinθ is a real number and 0 < θ < 2π, then θ is equal to

  • π

  • π6

  • π3

  • π2


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