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Sketch f(x) from f'(x) (1 Viewer)

_ShiFTy_

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From what i've gathered from doing one question, and looking at the answers...are these the main steps:

1) If the y = 0 , then stationarly point for f(x) curve
2) If stationairy point on f'(x) curve, then point of inflexion on f(x) curve?
3) If stationairy point AND y = 0 , then HORIZONTAL point of inflexion?

Is there anything else?
 
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Riviet

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_ShiFTy_ said:
From what i've gathered from doing one question, and looking at the answers...are these the main steps:

1) If the y = 0 , then stationarly point for f(x) curve
2) If stationairy point on f'(x) curve, then point of inflexion on f(x) curve?
3) If stationairy point AND y = 0 , then HORIZONTAL point of inflexion?

Is there anything else?
Those seem right, you could also consider when the gradient goes from positive to negative, ie from above x axis, cutting the x axis, then going below the x axis, how fast it's increasing and decreasing.
 

_ShiFTy_

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Just thought of a few things. What if there was a vertical asymptote on the f'(x) curve? Would this just mean that the gradient will keep on increasing/decreasing so it would look parabolic or something?
And also, if there was a vertical tangent on an f(x) curve, what would it look like on the f'(x) curve?
 

Riviet

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_ShiFTy_ said:
Just thought of a few things. What if there was a vertical asymptote on the f'(x) curve? Would this just mean that the gradient will keep on increasing/decreasing so it would look parabolic or something?
And also, if there was a vertical tangent on an f(x) curve, what would it look like on the f'(x) curve?
If there was a vertical asymptote on the f ' (x) curve, then the original f(x) will also have the same vertical asymptote, since the gradient is increasing to infinity.
I'm not sure about the vertical tangent on an f(x) curve. I don't think this one is important since if there was a vertical tangent, then the curve would be a relation. :p
 

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_ShiFTy_ said:
Just thought of a few things. What if there was a vertical asymptote on the f'(x) curve? Would this just mean that the gradient will keep on increasing/decreasing so it would look parabolic or something?
And also, if there was a vertical tangent on an f(x) curve, what would it look like on the f'(x) curve?
I believe Riviet is incorrect. These two problems are actually the same thing and one implies the other.

Consider the function of a half circle, at the endpoints the gradient becomes vertical and the derivative is asymptopical at that point.
 

Riviet

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Sorry, wasn't thinking properly with the vertical tangents, of course the function could have a vertical tangent at its end point. :eek:
 

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Riviet said:
Sorry, wasn't thinking properly with the vertical tangents, of course the function could have a vertical tangent at its end point. :eek:
Not just the end point, consider f(x)=x1/3 ;)
 

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