A line segment has endpoints at (3 , 4) and (1 ,9). If the line segment is rotated about the origin by (3pi)/2 , translated horizontally by -2, and reflected about the x-axis, what will the line segment's new endpoints be?

Apr 18, 2018

$\left(- 2 , 3\right) \text{ and } \left(7 , 1\right)$

Explanation:

$\text{Since there are 3 transformations to be performed label}$
$\text{the endpoints}$

$A \left(3 , 4\right) \text{ and } B \left(1 , 9\right)$

$\textcolor{b l u e}{\text{First transformation}}$

$\text{under a rotation about the origin of } \frac{3 \pi}{2}$

• " a point "(x,y)to(y,-x)

$\Rightarrow A \left(3 , 4\right) \to A ' \left(4 , - 3\right)$

$\Rightarrow B \left(1 , 9\right) \to B ' \left(9 , - 1\right)$

$\textcolor{b l u e}{\text{Second transformation}}$

$\text{under a translation } \left(\begin{matrix}- 2 \\ 0\end{matrix}\right)$

• " a point "(x,y)to(x-2,y)

$\Rightarrow A ' \left(4 , - 3\right) \to A ' ' \left(2 , - 3\right)$

$\Rightarrow B ' \left(9 , - 1\right) \to B ' ' \left(7 , - 1\right)$

$\textcolor{b l u e}{\text{Third transformation}}$

$\text{under a reflection about the x-axis}$

• " a point "(x,y)to(x,-y)

$\Rightarrow A ' ' \left(2 , - 3\right) \to A ' ' ' \left(2 , 3\right)$

$\Rightarrow B ' ' \left(7 , - 1\right) \to B ' ' ' \left(7 , 1\right)$

$\text{After all 3 transformations}$

$\left(3 , 4\right) \to \left(2 , 3\right) \text{ and } \left(1 , 9\right) \to \left(7 , 1\right)$