Match List with List II. List gives matrices representing transformations

2020

Matchย List Iย withย List II.ย List Iย givesย 3ร—3ย matrices representingย 2๐ทย transformations andย List IIย shows the corresponding transformation diagrams.

Choose the correct answer from the options given below:

  1. A.

    ๐ดโˆ’๐ผ๐‘‰,๐ตโˆ’๐ผ๐ผ,๐ถโˆ’๐ผ๐ผ๐ผ,๐ทโˆ’๐ผ

  2. B.

    ๐ดโˆ’๐ผ๐‘‰,๐ตโˆ’๐ผ๐ผ๐ผ,๐ถโˆ’๐ผ๐ผ,๐ทโˆ’๐ผ

  3. C.

    ๐ดโˆ’๐ผ๐ผ๐ผ,๐ตโˆ’๐ผ๐ผ,๐ถโˆ’๐ผ๐‘‰,๐ทโˆ’๐ผ

  4. D.

    ๐ดโˆ’๐ผ๐ผ,๐ตโˆ’๐ผ๐‘‰,๐ถโˆ’๐ผ๐ผ๐ผ,๐ทโˆ’๐ผ

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Correct answer: D

Solution overview: Identify each 3ร—3 homogeneous matrix by its effect on 2D coordinates, then match it to the appropriate diagram.

  • Matrix [2 0 0; 0 2 0; 0 0 1] โ†’ uniform scale by factor 2. Diagonal entries (2,2) scale x and y; this matches the scale diagram (scale (2,2)).

  • Matrix [1 0 2; 0 1 2; 0 0 1] โ†’ translation by (2, 2). The last column (2,2) gives the translation vector; this matches the translate diagram (translate (2,2)).

  • Matrix [0.5 -0.866 0; 0.866 0.5 0; 0 0 1] โ†’ rotation by 60ยฐ. Entries match cos60ยฐ = 0.5 and sin60ยฐ โ‰ˆ 0.866, so it is a rotation matrix; this matches the rotate(60ยฐ) diagram.

  • Matrix [1 2 0; 0 1 0; 0 0 1] โ†’ horizontal shear (x' = x + 2y). The off-diagonal 2 in the top-right produces a shear in the x-direction; this matches the shear diagram.

Final matching (matrix โ†’ diagram): [2 0 0; 0 2 0; 0 0 1] โ†’ scale, [1 0 2; 0 1 2; 0 0 1] โ†’ translate (2,2), [0.5 -0.866 0; 0.866 0.5 0; 0 0 1] โ†’ rotate 60ยฐ, [1 2 0; 0 1 0; 0 0 1] โ†’ shear.

Explore the full course: Dsssb Tgt Computer Science Paper 2