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# Is my maths good for d1

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1. (Original post by Jane122)
y>0?
Not completely incorrect but not completely correct either.

If you were given a graph and asked to find the range of the function on the graph, how would you find it? What is the definition of the range?
2. (Original post by Jane122)
whats the range of this graph y=2/x if the domain is x>2 ?

SeanFM maths123
Consider what y is when x=2 and what happens as x tends to infinity.
3. (Original post by SeanFM)
Not completely incorrect but not completely correct either.

If you were given a graph and asked to find the range of the function on the graph, how would you find it? What is the definition of the range?
smallest y value and y=0 is the smallest asymptote so?
4. (Original post by NotNotBatman)
Consider what y is when x=2 and what happens as x tends to infinity.
i have another q.
idk how to draw 2x+3/x-1 (her,x>1)
and find the domain and range of f-1(X)

I GOT THE RANGE OF F-1(X) AS YER, Y>1 since the domain on f(X) IS THE RANGE OF F-1(X)
5. (Original post by Jane122)
smallest y value and y=0 is the smallest asymptote so?
No, the range is not the smallest y value it is the range of ....
Spoiler:
Show
y values that exist.
6. (Original post by Jane122)
i have another q.
idk how to draw 2x+3/x-1 (her,x>1)
and find the domain and range of f-1(X)

I GOT THE RANGE OF F-1(X) AS YER, Y>1 since the domain on f(X) IS THE RANGE OF F-1(X)
For divide top and bottom by x, so that you have and observe what happens for large values of x.
7. (Original post by SeanFM)
No, the range is not the smallest y value it is the range of ....
Spoiler:
Show
y values that exist.
i'm still confused. I don't know what the range is. so it was y>0?
8. (Original post by NotNotBatman)
For divide top and bottom by x, so that you have and observe what happens for large values of x.
why tho?

also i drew the graph of x^3+1 so is the range y> than equal to 1? but theres also negative Y values oh I'm confused gosh

SeanFM
9. (Original post by Jane122)
i'm still confused. I don't know what the range is. so it was y>0?
I have told you the definition of the range, so what is the definition? (and hence what is the answer to your question?)
10. (Original post by SeanFM)
I have told you the definition of the range, so what is the definition? (and hence what is the answer to your question?)
the y values that exist? so y>0?
11. (Original post by Jane122)
why tho?

also i drew the graph of x^3+1 so is the range y> than equal to 1? but theres also negative Y values oh I'm confused gosh
Why? Because it makes it easier to see what's happens. You could just sub in large values of x into the calculator, but sometimes that's not enough.

The range for is if the domain is unrestricted.
12. (Original post by NotNotBatman)
Why? Because it makes it easier to see what's happens. You could just sub in large values of x into the calculator, but sometimes that's not enough.

The range for is if the domain is unrestricted.
oh okay!! but you know how i put the graph passing through 1 do i ignore the 1 then? i don't get restricted and unrestricted..
13. (Original post by Jane122)
the y values that exist? so y>0?
Yes, the y values that exist now remember y = 2/x where x > 2.

So tell me, if y>0 (every value of y that is greater than 0) exists, when is y = 100? How about 10000?
14. (Original post by SeanFM)
Yes, the y values that exist now remember y = 2/x where x > 2.

So tell me, if y>0 (every value of y that is greater than 0) exists, when is y = 100? How about 10000?
i said y>0 first....

would it be 0<y<1?
15. (Original post by Jane122)
i said y>0 first....

would it be 0<y<1?
See, well done hopefully you understand that now and how to tackle questions in the future (just by asking yourself what y values exist for the given x values)
16. (Original post by SeanFM)
See, well done hopefully you understand that now and how to tackle questions in the future (just by asking yourself what y values exist for the given x values)
thank you!!!!!!
17. (Original post by Jane122)
oh okay!! but you know how i put the graph passing through 1 do i ignore the 1 then? i don't get restricted and unrestricted..
What do you mean ignore the 1? The range is not determined by where this graph is crossing the y axis, it is from the smallest y can be and the greatest y can be and that is between and

An exception is when there is a discontinuous curve, this is where there would be a gap in the curve.

Unrestricted domain means x can be any real number, written as
Restricted domain is where the function can only take on a certain range of x values. So if it was then the domain is restricted from to
18. (Original post by NotNotBatman)
What do you mean ignore the 1? The range is not determined by where this graph is crossing the y axis, it is from the smallest y can be and the greatest y can be and that is between and

An exception is when there is a discontinuous curve, this is where there would be a gap in the curve.

Unrestricted domain means x can be any real number, written as
Restricted domain is where the function can only take on a certain range of x values. So if it was then the domain is restricted from to
19. (Original post by Jane122)
Only if the domain is x>0

If it is unrestricted, then y belongs to the set of real numbers.
20. (Original post by notnotbatman)
only if the domain is x>0

if it is unrestricted, then y belongs to the set of real numbers.
ohhh i see!!! Thanks again batman!!!! Xxxx

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