Home
Class 12
MATHS
A person walks 2sqrt(2) units away from ...

A person walks `2sqrt(2)` units away from origin in south west direction `(S45^(@)W)` to reach `A`, then walks `sqrt(2)` units in south east direction `(S45^(@)E)` to reach `B`. From `B` he travel is `4` units horizontally towards east to reach `C`. Then he travels along a circular path with centre at origin through an angle of `2pi//3` in anti-clockwise direction to reach his destination `D`.
Position of `D` in argand plane is (`w` is an imaginary cube root of unity)

A

`(3+i)omega`

B

`-(1+i)omega^(2)`

C

`3(1-i)omega`

D

`(1-3i)omega`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem step by step, we will determine the coordinates of points A, B, C, and D in the Argand plane. ### Step 1: Determine the coordinates of point A The person walks `2√2` units in the southwest direction (S45°W). In the Argand plane, this direction corresponds to an angle of 225° (or 5π/4 radians). Using the polar to rectangular conversion: - \( A = 2\sqrt{2} \left( \cos(225°) + i \sin(225°) \right) \) Calculating: - \( \cos(225°) = -\frac{1}{\sqrt{2}} \) - \( \sin(225°) = -\frac{1}{\sqrt{2}} \) Thus, \[ A = 2\sqrt{2} \left( -\frac{1}{\sqrt{2}} - i \frac{1}{\sqrt{2}} \right) = -2 - 2i \] ### Step 2: Determine the coordinates of point B From point A, the person walks `√2` units in the southeast direction (S45°E), which corresponds to an angle of 135° (or 3π/4 radians). Using the polar to rectangular conversion: - \( B = A + \sqrt{2} \left( \cos(135°) + i \sin(135°) \right) \) Calculating: - \( \cos(135°) = -\frac{1}{\sqrt{2}} \) - \( \sin(135°) = \frac{1}{\sqrt{2}} \) Thus, \[ B = (-2 - 2i) + \sqrt{2} \left( -\frac{1}{\sqrt{2}} + i \frac{1}{\sqrt{2}} \right) = (-2 - 2i) + (-1 + i) = -3 - i \] ### Step 3: Determine the coordinates of point C From point B, the person travels `4` units horizontally towards the east. Thus, the coordinates of point C will be: \[ C = B + 4 = (-3 - i) + 4 = 1 - i \] ### Step 4: Determine the coordinates of point D Now, the person travels along a circular path with center at the origin through an angle of \( \frac{2\pi}{3} \) in an anti-clockwise direction from point C. The position of point C in polar form is: - \( r = |C| = \sqrt{1^2 + (-1)^2} = \sqrt{2} \) - \( \theta = \tan^{-1}\left(\frac{-1}{1}\right) = -\frac{\pi}{4} \) Now, we add \( \frac{2\pi}{3} \) to the angle: \[ \theta_D = -\frac{\pi}{4} + \frac{2\pi}{3} = -\frac{3\pi}{12} + \frac{8\pi}{12} = \frac{5\pi}{12} \] Now, we convert back to rectangular coordinates: \[ D = r \left( \cos\left(\frac{5\pi}{12}\right) + i \sin\left(\frac{5\pi}{12}\right) \right) = \sqrt{2} \left( \cos\left(\frac{5\pi}{12}\right) + i \sin\left(\frac{5\pi}{12}\right) \right) \] Calculating: - \( \cos\left(\frac{5\pi}{12}\right) = \frac{\sqrt{6} - \sqrt{2}}{4} \) - \( \sin\left(\frac{5\pi}{12}\right) = \frac{\sqrt{6} + \sqrt{2}}{4} \) Thus, \[ D = \sqrt{2} \left( \frac{\sqrt{6} - \sqrt{2}}{4} + i \frac{\sqrt{6} + \sqrt{2}}{4} \right) = \frac{\sqrt{12} - \sqrt{4}}{4} + i \frac{\sqrt{12} + \sqrt{4}}{4} = \frac{2\sqrt{3} - 2}{4} + i \frac{2\sqrt{3} + 2}{4} \] \[ D = \frac{\sqrt{3} - 1}{2} + i \frac{\sqrt{3} + 1}{2} \] ### Final Position of D Thus, the position of D in the Argand plane is: \[ D = \frac{\sqrt{3} - 1}{2} + i \frac{\sqrt{3} + 1}{2} \]

To solve the problem step by step, we will determine the coordinates of points A, B, C, and D in the Argand plane. ### Step 1: Determine the coordinates of point A The person walks `2√2` units in the southwest direction (S45°W). In the Argand plane, this direction corresponds to an angle of 225° (or 5π/4 radians). Using the polar to rectangular conversion: - \( A = 2\sqrt{2} \left( \cos(225°) + i \sin(225°) \right) \) ...
Promotional Banner

Topper's Solved these Questions

  • COMPLEX NUMBERS

    CENGAGE ENGLISH|Exercise ILLUSTRATION|110 Videos
  • COMPLEX NUMBERS

    CENGAGE ENGLISH|Exercise SLOVED EXAMPLES|15 Videos
  • COMPLEX NUMBERS

    CENGAGE ENGLISH|Exercise Multiple Correct Answer|11 Videos
  • CIRCLES

    CENGAGE ENGLISH|Exercise Comprehension Type|8 Videos
  • CONIC SECTIONS

    CENGAGE ENGLISH|Exercise All Questions|101 Videos

Similar Questions

Explore conceptually related problems

If the axes are rotated through an angle of 30^@ in the anti clockwise direction, then coordinates of point (4,-2sqrt3) with respect to new axes are

If the axes are rotated through an angle of 45^(@) in the clockwise direction, the coordinates of a point in the new systeme are (0,-2) then its original coordinates are

A car is moving in east direction. It takes a right turn and moves along south direction without change in its speed. What is the direction of average acceleration of the car?

Find the coordinatse of the points at a distance 4sqrt(2) units from the point (-2, 3) in the direction making an angle of 45^0 with the positive direction of x-axis.

Find the equation of a line which intersects Y -axis at a distance of 4 units above origin and makes an angle of 45^(@) from positive direction of X -axis.

A body is thrown horizontally from the top of a tower. It reaches the ground after 4s at an angle 45° to the ground. The velocity of projection is

A man walk 20 m at an angle 60^(@) north of east . How far towards east has he he travellled ?

The point (4,1) undergoes the following three successive transformations , reflection about the line y = x-1 translation through a distance 1 unit along the positive direction rotation thrpough an angle pi/4 about the origin in the anti - clockwise direction Then the coordinates of the final point are ,

A particle P starts from the point z_0=1+2i , where i=sqrt(-1) . It moves first horizontally away from origin by 5 units and then vertically away from origin by 3 units to reach a point z_1dot From z_1 the particle moves sqrt(2) units in the direction of the vector hat i+ hat j and then it moves through an angle pi/2 in anticlockwise direction on a circle with centre at origin, to reach a point z_2dot The point z_2 is given by (a) 6+7i (b) -7+6i (c) 7+6i (d) -6+7i

A person moves 30 m north, , then 20 m towards east and finally 30sqrt(2) m in south-west direction. The displacement of the person from the origin will be