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Cubic graphs - before C1 tomorrow :/ Watch

1. AAAH! C1 AND C2 TOMORROW!
So, I'm confused about drawing cubic graphs... for example:
i have the graph x^3 + 7x^2 + 7x - 15 which equals: (x+3)(x+5)(x-1) so i know the graph crosses/touches the x-axis at -3,-5 and 1, and it crosses the y axis at -15...
What i want to know is how you know when it touches the x-axis and when it actually crosses it? basically drawing it...
2. (Original post by sesrugeda)
AAAH! C1 AND C2 TOMORROW!
So, I'm confused about drawing cubic graphs... for example:
i have the graph x^3 + 7x^2 + 7x - 15 which equals: (x+3)(x+5)(x-1) so i know the graph crosses/touches the x-axis at -3,-5 and 1, and it crosses the y axis at -15...
What i want to know is how you know when it touches the x-axis and when it actually crosses it? basically drawing it...
If it just touches the x axis (the x axis is a tangent to the curve) then there will be a repeated factor such as .
3. (Original post by Mr M)
If it just touches the x axis (the x axis is a tangent to the curve) then there will be a repeated factor such as .
Thank you that was such an easy answer! haha! so if it's repeated, it touches the axis, if it's not it crosses it Thanks again! have you got the exam tomorrow? if you do, good luck!
4. (Original post by sesrugeda)
Thank you that was such an easy answer! haha! so if it's repeated, it touches the axis, if it's not it crosses it Thanks again! have you got the exam tomorrow? if you do, good luck!
My exam days are over. Good luck to you.
5. (Original post by Mr M)
My exam days are over. Good luck to you.
Thank you

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Updated: May 12, 2013
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