Limits of a function's derivative and how it relates to a function.

In summary, the derivative of a function is the rate of change of the function at a specific point and has many important applications in mathematics, physics, and engineering. The limit of a function and its derivative are closely related, and the limit of a function's derivative can be used to determine the continuity of the function at a specific point. A function may not have a derivative at all points, only at points where it is continuous and differentiable.
  • #1
renjean
7
0

Homework Statement



Prove or disprove: if lim x->b (from the left) f'(x) = infinity then lim x->b (from the left) f(x) = infinity


Homework Equations


my gut instinct is that this is false.


The Attempt at a Solution


I have thought of many counterexamples but none of them seem to work. Does it matter that the limit is at a point and not as x-> infinity?
 
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  • #2
Hint: (f-1)'=1/f'(f-1(x))

What happens if f'(y)=0.
 
  • #3
ah! that helps a lot. thanks for the hint!
 

FAQ: Limits of a function's derivative and how it relates to a function.

What is the definition of the derivative of a function?

The derivative of a function is the rate of change of the function at a specific point. It measures how much the output of the function changes for a small change in the input value at that point.

How are the limit of a function and its derivative related?

The limit of a function at a certain point is the same as the derivative of the function at that point, as long as the derivative exists at that point. This means that the limit of a function and its derivative are closely linked and can be used to understand each other.

What is the significance of the derivative of a function?

The derivative of a function has many important applications in mathematics, physics, and engineering. It can be used to find the maximum and minimum values of a function, determine the slope of a tangent line to a curve, and solve optimization problems. It also helps us understand the behavior of a function at a specific point.

Can a function have a derivative at all points?

No, a function may not have a derivative at all points. A function can only have a derivative at points where it is continuous and differentiable. This means that the function must be defined and smooth at that point.

How can the limit of a function's derivative be used to determine the continuity of the function?

If the limit of a function's derivative exists at a point, it means that the function is differentiable at that point. This also implies that the function is continuous at that point. Therefore, the limit of a function's derivative can be used to determine the continuity of the function at a specific point.

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