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How are my answers to these translations of the equations wrong ?

If you put them in on demos it even shows the described transformations..
Reply 1
Screenshot 2020-06-02 at 12.32.23.png
Original post by lhh2003
Screenshot 2020-06-02 at 12.32.23.png

1. Reflect in the y-axis:

y=logxy = \log x becomes y=log(x)y = \log(-x)



2. Translate by (-4,5)

y=log(x)y = \log(-x) becomes y5=log((x+4))y-5 = \log(-(x+4))
Reply 3
Original post by RDKGames
1. Reflect in the y-axis:

y=logxy = \log x becomes y=log(x)y = \log(-x)



2. Translate by (-4,5)

y=log(x)y = \log(-x) becomes y5=log((x+4))y-5 = \log(-(x+4))

Why does y=log(x)y = \log(-x) become y5=log((x+4))y-5 = \log(-(x+4)) ? That would suggest that you perform the translation before you do the reflection. Yet, the question wants the reflection before the translation, so why is 2. not y=log(x+4)+5 y = log(-x + 4) + 5 ?
Original post by lhh2003
Why does y=log(x)y = \log(-x) become y5=log((x+4))y-5 = \log(-(x+4)) ? That would suggest that you perform the translation before you do the reflection. Yet, the question wants the reflection before the translation, so why is 2. not y=log(x+4)+5 y = log(-x + 4) + 5 ?

It does not suggest that we do translation before the reflection.

We have already done the reflection.

If we are to do translation before the reflection, then the order would be:

1. Translation by (-4,5) -- this means replace y with y-5 and x with x+4.

y=logxy = \log x becomes y5=log(x+4)y-5 = \log(x+4)



2. Reflection in the y-axis -- this means replace x with -x

5=log(x+4)-5 = \log(x+4) becomes y5=log(x+4)y-5 = \log(-x+4)
Reply 5
Original post by RDKGames
It does not suggest that we do translation before the reflection.

We have already done the reflection.

If we are to do translation before the reflection, then the order would be:

1. Translation by (-4,5) -- this means replace y with y-5 and x with x+4.

y=logxy = \log x becomes y5=log(x+4)y-5 = \log(x+4)



2. Reflection in the y-axis -- this means replace x with -x

5=log(x+4)-5 = \log(x+4) becomes y5=log(x+4)y-5 = \log(-x+4)

Ahh ok, I see know know what I don't understand.

If you are multiplying 4 by -1 then surely this indicates that the reflection will affect the 4 as well ?

Is there a video I could watch that explains this fully ?

Thanks.

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