The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

weird maths question

the graph of y=f(x) is transformed to give the graph y=-f(x+3)
the point A on the graph of y=f(x) is mapped to the point P on the graph of y=-f(x+3)
the coordinates of point A are 9,1
Find coordinates of point P

im very confused as how to do this question, im aware what the transfomation is which is 3 to the left, but 3 to the left from where? how am i suppose to know what P originally was? thanks
What happens to the x values and y values after that transformation. Apply those changes to the x and y coordinates of the point to obtain new ones.
P was originally A if you read the question carefully.
Point A (9,1), apply the first part of the transformation (x+3) as you correctly said it moves it 3 to the left giving the new coordinate (6,1)
Now let’s apply the minus giving us the point
P (-6,-1). I haven’t done maths in a while
But that should be correct
You need to be aware of the steps taken to transform the graph from y=f(x) to y=-f(x+3). For each step your x and y coordinate values will change. So starting with (9,1) apply each change to the coordinates depending on the change to the graph
Original post by Howie_2114
Point A (9,1), apply the first part of the transformation (x+3) as you correctly said it moves it 3 to the left giving the new coordinate (6,1)
Now let’s apply the minus giving us the point
P (-6,-1). I haven’t done maths in a while
But that should be correct


Why the **** has 6 changed into -6?
Original post by Radioactivedecay
What happens to the x values and y values after that transformation. Apply those changes to the x and y coordinates of the point to obtain new ones.


they move 3 to the left, but im confused as to what P is, it doesnt say what the gradient of the line is so how do i know where P originally was so i can apply the trainsformation?
Original post by Gent2324
they move 3 to the left, but im confused as to what P is, it doesnt say what the gradient of the line is so how do i know where P originally was so i can apply the trainsformation?


P is orignally A. Read the question carefully.
Original post by Radioactivedecay
P is orignally A. Read the question carefully.


so does mapped mean changes into?
Original post by Math12345
Why the **** has 6 changed into -6?


Because the transformation is -f(x+3), once you’ve done the (x+3) you multiply that new coordinate by -1 to give the final coordinate P
Original post by Gent2324
the graph of y=f(x) is transformed to give the graph y=-f(x+3)
the point A on the graph of y=f(x) is mapped to the point P on the graph of y=-f(x+3)
the coordinates of point A are 9,1
Find coordinates of point P

im very confused as how to do this question, im aware what the transfomation is which is 3 to the left, but 3 to the left from where? how am i suppose to know what P originally was? thanks


The transformation isn't just 3 to the left tho is it. If the -ve is outside the f(x) then it's gunna multiply all the values of f(x) by -1, which will essentially reflect it in the x axis.

If you know P, which is f(x) then you start from inside the brackets when you do these questions, so firstly move to the left by 3 like you rightly said. Then you can reflect it in the x axis and ta da
(edited 6 years ago)
Original post by Howie_2114
Because the transformation is -f(x+3), once you’ve done the (x+3) you multiply that new coordinate by -1 to give the final coordinate P




-f(x+3) is the transformations: translation vector (-3 , 0) and reflection in the line y=0 (x-axis).
(edited 6 years ago)
Original post by BDunlop
The transformation isn't just 3 to the left tho is it. If the -ve is outside the f(x) then it's gunna multiply all the values of f(x) by -1, which will essentially reflect it in the Y axis.

If you know P, which is f(x) then you start from inside the brackets when you do these questions, so firstly move to the left by 3 like you rightly said. Then you can reflect it in the Y axis and ta da


Original post by Radioactivedecay
P is orignally A. Read the question carefully.


Original post by Y11_Maths
You need to be aware of the steps taken to transform the graph from y=f(x) to y=-f(x+3). For each step your x and y coordinate values will change. So starting with (9,1) apply each change to the coordinates depending on the change to the graph


Original post by Howie_2114
Point A (9,1), apply the first part of the transformation (x+3) as you correctly said it moves it 3 to the left giving the new coordinate (6,1)
Now let’s apply the minus giving us the point
P (-6,-1). I haven’t done maths in a while
But that should be correct


great thanks everyone i think i get it now, you -3 and then you flip the Y value, its just a case of weirdly worded questions that confuse me :biggrin:
The amount of wrong answers on this thread *shaking my head*
Original post by Math12345
The amount of wrong answers on this thread *shaking my head*


which ones are wrong other than -6,-1 ?
Original post by BDunlop
which ones are wrong other than -6,-1 ?


You just changed y-axis to x-axis :wink:
Original post by Math12345
You just changed y-axis to x-axis :wink:


no I totally didn't..*walk of shame*

embarrassing mistake, doesn't reflect my maths :wink:
It wasn't weirdly worded, you just have to break it down into steps.I would do the horizontal changes first, then the vertical, but it doesn't really matter.

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you