Question

A segment with endpoints (3, 9) and (2, 1) is reflected across the line y = x. Which matrix expression represents the transformation?

Answer 1

@hartnn

Answer 2

flipping across the y=x line will make the ys,xs and xs ys

Answer 3

so option d

Answer 4

wait a second.. that might not be right

Answer 5

its option b

Answer 6

option d only switches the rows

Answer 7

option b gives us what we want exapand it to see

Answer 8

lol why the given points are not there in any of the options

Answer 9

ohh i took it to be -3

Answer 10

i didnt think theyd play this kind of a trick on you!

Answer 11

\[

\left[ \begin{array}{cc}
x \\
y \\
\end{array} \right]

\to

\left[ \begin{array}{cc}
y \\
x \\
\end{array} \right]
\]

Answer 12

haaha clearly its a row switching so the transformation matrix need to be on left side
so either C or D is the right option... but they dont have correct input points :/

Answer 13

hey but that row switching operations wont that still produce the same row operations on an x
y column matrix

Answer 14

something like below, right ?

\[
\left[ \begin{array}{cc}
0 & 1 \\
1 & 0\\
\end{array} \right] \bullet
\left[ \begin{array}{cc}
3 & 2 \\
9 & 1\\
\end{array} \right]

\]

Answer 15

there's the full question

Answer 16

only options are visible ^ check once..

Answer 17

ganeshi can u explain

Answer 18

nevermind i get it

Answer 19

its D, you need to only do row switching operation in this case

Answer 20

the top column are the set of Xs and the bottom are your Ys
so switching the Xs and the Ys give us reflection on y=x

Answer 21

the top row*

Answer 22

I see... Can you help me translate an image up and to the left?

Answer 23

okay

Answer 24

with matrix right?

Answer 25

looks u r so much attached to the previous problem :P

Answer 26

Lol sorry, the snapshots keep messing up :/

Answer 27

option B will work for xy plane

Answer 28

\(
\left[ \begin{array}{ccc}
1 & 0 & \color{red}{-2} \\
0 & 1 & \color{red}{4} \\
0 & 0 & 1 \\
\end{array} \right] \bullet
\left[ \begin{array}{ccx}
x \\
y\\
1 \\
\end{array} \right]
=
\left[ \begin{array}{ccx}
x-2 \\
y+4\\
1 \\
\end{array} \right]
\)