A ray of light is reflected off a mirror such that the reflected ray is perpendicular to the original ray, as shown in the diagram. What is the equation of the reflected ray?
y – x = 6
y + x = 6
-y + x = 6
y + x = 5
y – x = 5

Question

A ray of light is reflected off a mirror such that the reflected ray is perpendicular to the original ray, as shown in the diagram. What is the equation of the reflected ray?
y – x = 6
y + x = 6
-y + x = 6
y + x = 5
y – x = 5

anonymous · Answer

|dw:1401920658994:dw|

phi · Answer

they tell you
the reflected ray is perpendicular to the original ray

First, what is the slope of the original ray ?

anonymous · Answer

The slope of the original ray is 1 and the slope of the reflected ray is -1.

phi · Answer

ok.  the other thing you know is that the point (1,5) is on the reflected ray

you can use
$$ y - y_0 = m(x-x_0) $$
where $ (x_0,y_0) $ is a point on the line, and m is the slope
and rearrange to match your choices.
can you do that?

anonymous · Answer

Is the answer y+x=6?

phi · Answer

you should do
y - 5 = -1(x-1)
and simplify
y- 5 = -x + 1
add +5 to both sides
y -5+5= -x +1+5

simplify to get
y = -x +6

add +x to both sides
x+y = 6

yes

phi · Answer

of course, y+x=6 is the same thing (order of adding does not matter)

anonymous · Answer

Ok Thanks

phi · Answer

yw