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Basic c2 graphs question

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    Say you are given the equation y = x(x^2-1) to sketch the roots are (-1,0) (0,0) (1,0)

    How would you sketch it I mean in terms of which side would you start of with how do you know where the max min points are.

    Also does anybody know what the graph of y=-srt of x look like?
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    (Original post by IShouldBeRevising_)
    Say you are given the equation y = x(x^2-1) to sketch the roots are (-1,0) (0,0) (1,0)

    How would you sketch it I mean in terms of which side would you start of with how do you know where the max min points are.

    Also does anybody know what the graph of y=-srt of x look like?
    The graph of  y= - \sqrt{x} looks like this:



    For the graph of,  y=x(x^2-1)

    You know the values where it crosses the x-axis, just consider all the regions, by subbing in some values to deduce the shape of the graph.

    e.g. It crosses at (1,0), see what is the value of y when x=2, if it is positive then the graph will move upward and if it is negative, then the graph will move downwards.
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    (Original post by IShouldBeRevising_)
    Say you are given the equation y = x(x^2-1) to sketch the roots are (-1,0) (0,0) (1,0)

    How would you sketch it I mean in terms of which side would you start of with how do you know where the max min points are.

    Also does anybody know what the graph of y=-srt of x look like?
    I forgot to answer your other question about max/min points.

    Max/min occurs at stationary points where the gradient is equal to zero.

     y=x(x^2-1) = x^3-x

    Differentiate the above expression, and set dy/dx=0 to find the stationary points. Find the 2nd derivative to check whether the points are max or min.
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    (Original post by raheem94)
    I forgot to answer your other question about max/min points.

    Max/min occurs at stationary points where the gradient is equal to zero.

     y=x(x^2-1) = x^3-x

    Differentiate the above expression, and set dy/dx=0 to find the stationary points. Find the 2nd derivative to check whether the points are max or min.

    (Original post by raheem94)
    The graph of  y= - \sqrt{x} looks like this:



    For the graph of,  y=x(x^2-1)

    You know the values where it crosses the x-axis, just consider all the regions, by subbing in some values to deduce the shape of the graph.

    e.g. It crosses at (1,0), see what is the value of y when x=2, if it is positive then the graph will move upward and if it is negative, then the graph will move downwards.
    Thanks well explained... I get it now

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