how can you determine whether a design has rotational symmetry? if a design has a rotational symmetry, how many can you find the angle of roation??

  1. 👍
  2. 👎
  3. 👁
  1. rotation matrix for rotation angle T
    |cos T |-sin T|
    |sin T | cos T|
    That matrix, call it M
    then M (column x|y) gives new x|y
    for example if T = 90 degrees
    | 0 |-1 | [x]
    | 1 | 0 | [y]

    0 x - y = -y for new x value
    1 x + 0 y = x for new y value

    SO you can reverse that
    new x = old x cos T - old y sin T
    new y = old x sin T + old y cos T

    If you have a bunch of old x and y values and their corresponding new values, you can solve for sin T and Cos T and therefore for T, the rotation angle.

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. Physics

    A 21-kg child starts at the center of a playground merry-go-round that has a radius of 3.5 m and rotational inertia of 500 kg⋅m2 and walks out to the edge. The merry-go-round has a rotational speed of 0.20 s−1 when she is at

  2. AP Physics

    A light string that is attached to a large block of mass 4m passes over a pulley with negligible rotational inertia and is wrapped around a vertical pole of radius r. The system is released from rest, and as the block descends the

  3. geometry

    Which type(s) of symmetry does the uppercase letter H have? my answer i believe is reflectional symmetry Which type of symmetry is shown by the lowercase letter w? my answer i believe is rotational symmetry. Could someone please

  4. Maths

    Which letter has rotational symmetry? a. I b. J c. B d. R I think it is A.

  1. Math

    Which uppercase letters of the alphabet have rotational symmetry?

  2. Art

    Why do some people feel the wall for peace in Paris is unsightly? The contemporary design was poorly constructed and falling apart. The contemporary design dose not convey ideas of peace with enough clarity.•• The contemporary

  3. Physics

    At the start of your throw of a 5.6-kg bowling ball, your arm is straight behind you and horizontal (Figure 1) . Your arm is 0.64 m long, has a rotational inertia of 0.48 kg⋅m2 and has a mass of 3.5 kg with its center of mass

  4. Geometry

    What is a quadrilateral that has both reflectional and rotational symmetry?

  1. Drafting and Design

    Select the correct answer from each drop-down menu. Which pencil should Edward use? Edward is creating a new design for his latest assignment. He first uses a (5B, 3B, 3H) to create a rough sketch for the design. Once he is

  2. ap physics

    Determine the change in rotational kinetic energy when the rotational velocity of the turntable of a stereo system increases from 0 to 33 rpm. Its rotational inertia is 6.8×10−3kg⋅m2 .

  3. Math

    what is a figure that has only rotational symmetry? and what is its angle of rotation?

  4. math

    what are the different axes of rotational symmetry for a pentagonal pyramid?

You can view more similar questions or ask a new question.