Simple reflection and translation question

AI Thread Summary
The discussion centers on transforming the graph of the function 1/x through reflection in the y-axis and subsequent translations. The correct transformations involve reflecting the function to get y = f(-x), translating it 3/4 units to the right (which requires a negative sign), and then translating it 2 units up. The final equation derived is y = 1/(0.75 - x) + 2, which simplifies to y = 4/(3 - 4x) + 2. The original suggested answer D) is deemed incorrect, highlighting a misunderstanding in the transformation process.
nothingsus
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Homework Statement



If the graph of 1/x is reflected in the y-axis, translated 3/4 units to the right and 2 units up, the resulting graph would have the equation...

A) 1/(x-2) + 0.75
B) 3/(4x) +2
C) 2 - 1/(3/4x)
D) -1/(4x-3) + 2
E) 1/(3-4x) + 2

2. The attempt at a solution
So the general formula of a hyperbola is y = a/(x-b) + c (in this context anyway, I know there's another form)

reflection in the y-axis -> y=f(-x)
translated 3/4 right -> b=3/4
translated 2 up -> c=2

So if I put it all together I get
y = 1/(-x-b) + c
y = 1/(-x-0.75) + 2
= 1/-(x+0.75) + 2
= -1/(x+0.75) +2

The correct answer was D)
 
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nothingsus said:

Homework Statement



If the graph of 1/x is reflected in the y-axis, translated 3/4 units to the right and 2 units up, the resulting graph would have the equation...

A) 1/(x-2) + 0.75
B) 3/(4x) +2
C) 2 - 1/(3/4x)
D) -1/(4x-3) + 2
E) 1/(3-4x) + 2

2. The attempt at a solution
So the general formula of a hyperbola is y = a/(x-b) + c (in this context anyway, I know there's another form)

reflection in the y-axis -> y=f(-x)
translated 3/4 right -> b=3/4
translated 2 up -> c=2

So if I put it all together I get
y = 1/(-x-b) + c
y = 1/(-x-0.75) + 2
= 1/-(x+0.75) + 2
= -1/(x+0.75) +2

The correct answer was D)

I don't get any of your suggested answers, and your answer is also wrong.

When you do the reflection about the y-axis, ##y = f(x)## becomes ##y = f(-x) = g(x)## (say).

When you do the translation to the RIGHT by 0.75, ##y = g(x)## becomes ##y = g(x-0.75)## (note the minus sign here).

Now ##g(x - 0.75) = g(-(0.75 - x)) = f(0.75 - x)## since ##g(-x) = f(x)##.

When you finally do the vertical translation upward, you get ##y = f(0.75 - x) + 2##.

So the final answer is ##y = f(0.75 - x) + 2 = \frac{1}{0.75-x} + 2 = \frac{4}{3-4x} + 2## after simplification.

If there wasn't a 4 in the numerator in any of the suggested answers, the question is likely wrong.
 
D is not quite correct. It should be y=-1/(x-3/4)+2 or y=-4/(4x-3)+2.
There is a mistake in your derivation:
If you shift a function y=f(x) to the right by A the new function is y=f(x-A). (Think: the new function has its asymptote where it goes to infinity at x=3/4)

ehild
 
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