Is my maths good for d1

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    (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?
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    (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.
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    (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?
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    (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)
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    (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.
    That should help you answer your question and to see why y>0 is not completely correct but not completely incorrect.
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    (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  \frac{2x+3}{x-1} divide top and bottom by x, so that you have  \frac{2 +\frac{3}{x}}{1 - \frac{1}{x}} and observe what happens for large values of x.
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    (Original post by SeanFM)
    No, the range is not the smallest y value it is the range of ....
    Spoiler:
    Show
    y values that exist.
    That should help you answer your question and to see why y>0 is not completely correct but not completely incorrect.
    i'm still confused. I don't know what the range is. so it was y>0?
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    (Original post by NotNotBatman)
    For  \frac{2x+3}{x-1} divide top and bottom by x, so that you have  \frac{2 +\frac{3}{x}}{1 - \frac{1}{x}} 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
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    (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?)
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    (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?
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    (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 y =x^3 +1 is  y \in \mathbb{R} if the domain is unrestricted.
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    (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 y =x^3 +1 is  y \in \mathbb{R} 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..
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    (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?
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    (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?
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    (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)
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    (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!!!!!!
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    (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  - \infty and  \infty

    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  x \in \mathbb{R}
    Restricted domain is where the function can only take on a certain range of x values. So if it was  y = x^3 + 1 , -3 \leq x\leq 3 then the domain is restricted from  x=-3 to  x=3
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    (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  - \infty and  \infty

    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  x \in \mathbb{R}
    Restricted domain is where the function can only take on a certain range of x values. So if it was  y = x^3 + 1 , -3 \leq x\leq 3 then the domain is restricted from  x=-3 to  x=3
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    (Original post by Jane122)
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    Only if the domain is x>0

    If it is unrestricted, then y belongs to the set of real numbers.
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    (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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