ROBLEMS ON REFLECTION ACROSS THE Y AXIS

The rule of reflection about y-axis is

(x, y) ==> (-x, y)

What is preimage ?

Preimage In a transformation, the original figure is called the preimage.

What is image ?

Image In a transformation, the final figure is called the image.

Graph the image of the figure using the transformation given.

Problem 1 :

Solution :

Marking the point U (2, -3). Reflection of U across y-axis is

U’ (-2, -3)

Problem 2 :

Reflection across the y-axis

Y (2, 2)

Solution :

Marking the point Y (2, 2). Reflection of Y across y-axis is

Problem 3 :

Reflection on y-axis

Solution : 

Marking the point K (2, -2). Reflection of K across y-axis is

K’ (-2, -2)

Problem 4 :

Solution :

By observing the figure, coordinates of the vertices are

C (1, -1), E (0, -1), M (3, -3) and W (1, -3)

C (1, -1) ==> C’ (-1, -1)

E (0, -1) ==> E’ (0, -1)

M (3, -3) ==> M’ (-3, -3)

W (1, -3) ==> W’ (-1, -3)

Problem 5 :

Reflection across y-axis

Solution :

By observing the figure, coordinates of the vertices are

W (-4, 0), I (-1, -1) and X (-3, -5)

W (-4, 0) ==> W’ (4, 0)

I (-1, -1) ==> I’ (1, -1)

X (-3, -5) ==> X’ (3, -5)

Problem 6 :

Reflection across the y-axis

D (-2, -3), E (2, -2) and F (3, -4)

Solution :

Rule:

(x, y) ==> (-x, y)

D (-2, -3) ==> D’ (2, -3)

E (2, -2) ==> E’ (-2, -2)

F (3, -4) ==> F’ (-3, -4)

Problem 7:

Solution:

By observing the figure, coordinates of the vertices are

I (4, 0), J (0, 2), K (-2, -1) and L (0, -3)

I (4, 0) ==> I’ (-4, 0)

J (0, 2) ==> J’ (0, 2)

K (-2, -1) ==> K’ (2, -1)

L (0, -3) ==> L’ (0, -3)

Problem 8:

Reflection across the y-axis

J (-2, -4), K (-3, -1), L (-1, -1), M (2, -5)

Solution:

Rule:

(x, y) ==> (-x, y)

J (-2, -4) ==> J’ (2, -4)

K (-3, -1) ==> K’ (3, -1)

L (-1, -1) ==> L’ (1, -1)

M (2, -5) ==> M’ (-2, -5)