A line segment has endpoints at (3 , 1)(3,1) and (2 ,3)(2,3). If the line segment is rotated about the origin by pi π, translated horizontally by 44, and reflected about the x-axis, what will the line segment's new endpoints be?

2 Answers
Jan 28, 2018

The new endpoints are (1,1)(1,1) and (2,3)(2,3).

Explanation:

Let's apply each of the transformations to both points, one at a time:

piπ rotation around the origin (180º):
(x,y)=>(-x,-y)(x,y)(x,y)
(3,1)=>(-3,-1)(3,1)(3,1)
(2,3)=>(-2,-3)(2,3)(2,3)

Horizontal translation by 44:
(x,y)=>(x+4,y)(x,y)(x+4,y)
(-3,-1)=>(1,-1)(3,1)(1,1)
(-2,-3)=>(2,-3)(2,3)(2,3)

Reflection over the xx-axis:
(x,y)=>(x,-y)(x,y)(x,y)
(1,-1)=>(1,1)(1,1)(1,1)
(2,-3)=>(2,3)(2,3)(2,3)

The new endpoints are (1,1)(1,1) and (2,3)(2,3).

Jan 28, 2018

(1,1)" and "((2,3)(1,1) and ((2,3)

Explanation:

"since there are 3 transformations to be performed here"since there are 3 transformations to be performed here

"label the endpoints "A(3,1)" and "B(2,3)label the endpoints A(3,1) and B(2,3)

color(blue)"First transformation"First transformation

"under a rotation about the origin by "piunder a rotation about the origin by π

• " a point "(x,y)to(-x,-y) a point (x,y)(x,y)

rArrA(3,1)toA'(-3,-1)

rArrB(2,3)toB'(-2,-3)

color(blue)"Second transformation"

"under a translation "((4),(0))

• " a point "(x,y)to(x+4,y)

rArrA'(-3,-1)toA''(1,-1)

rArrB'(-2,-3)toB''(2,-3)

color(blue)"Third transformation"

"under a reflection in the x-axis "

• " a point "(x,y)to(x,-y)

rArrA''(1,-1)toA'''(1,1)

rArrB''(2,-3)toB'''(2,3)

"after all 3 transformations"

(3,1)to(1,1)" and "(2,3)to(2,3)