Maths Question (Symmetry & Transformation)

Shing Hin

2008-05-04 10:14 pm

1. L is a line in the rectangular coordinate plane parallel to the y-axis and it passes through a point M(-1,3).
a) If a point Q is the image when a point P(-2,-2) is reflected in L, find the coordinates of Q.
b) If a point R is the image when M is reflected in a horizontal line passing through Q in part(a), find the coordinates of R.
c) If a point S is the image when M is reflected in a vertical line passing through Q in part(a), find the coordinates of S.

2. Try to find ot a simple way for each of the following to transform the point A to the point B.\
a) A(3,5) , B(-1,-4)
b) A(-2,4) , B(2,-2)
c) A(2,5) , B(-5,2)

回答 (1)

用戶82723

2008-05-07 11:27 pm

✔ 最佳答案

1. The equation of L is x = -1, as it is parallel to y-axis.
a) Coordiates of Q = (0, -2)
When P is reflected about L, its y-coordiate remains unchanged
while its x-coordinate changes to 0 such that P and Q are equidistance to L. (In this case, the distance is 1)
b) The horizontal line passing through Q is y = -2
So, similar to (a), coordinates of R = (0, -7)
c) Similarly, coordinates of S = (0,3)
2a) Move A to the left by 4 units, then move downwards by 9 units.
b) Move A to the right by 4 units, then move downwards by 6 units.
c) Rotate A anti-clockwisely about the origin by 90 degrees.

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