Mathematics
(i) Plot the points A(3, 5) and B(-2, -4). Use 1 cm = 1 unit on both the axes.
(ii) A' is the image of A when reflected in the x-axis. Write down the co-ordinates of A' and plot it on the graph paper.
(iii) B' is the image of B when reflected in the y-axis, followed by reflection in the origin. Write down the co-ordinates of B' and plot it on the graph paper.
(iv) Write down the geometrical name of the figure AA'BB'.
(v) Name two invariant points under reflection in the x-axis.
Reflection
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Answer
(i) The graph is shown below:
(ii) From graph,
Co-ordinates of A' = (3, -5).
(iii) Let B" be the point after reflection of B in y-axis.
From graph,
Co-ordinates of B' = (-2, 4).
(iv) From graph,
Figure AA'BB' is an isosceles trapezium.
(v) Invariant points to a line are points which lie on the line.
So, points invariant under reflection in x-axis lie on x-axis.
These can be any points with ordinate = 0.
Hence, (5, 0) and (-17, 0) are invariant points.
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Related Questions
A point P(a, b) is reflected in the x-axis to P'(2, -3), write down the values of a and b. P'' is the image of P, when reflected in the y-axis. Write down the coordinates of P''. Find the coordinates of P''', when P is reflected in the line, parallel to y-axis such that x = 4.
Points A and B have co-ordinates (3, 4) and (0, 2) respectively. Find the image :
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