Twice-differentiable Function and Etc.

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Since the function is increasing and concave up, the slope of the tangent line at x = 5 must be smaller than the slope of the tangent line at x = 6. That eliminates 27 from the list of possible choices for g(6).In summary, based on the given information that g is a twice-differentiable function with g'(x) > 0 and g"(x) > 0 for all real numbers of x, and g(4) = 12 and g(5) = 18, we can determine that the possible value for g(6) is either 15, 18, 21, or 24. The function is increasing and concave up, so the slope of
  • #1
MorganJ
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1. Let g be a twice-differentiable function with g'(x)>0 and g"(x)>0 for all real numbers of x, such that g(4)=12 and g(5) = 18. Of the following, which is the possible value for g(6)?



2.I honestly have no idea where to start :-(
 
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  • #2
MorganJ said:
1. Let g be a twice-differentiable function with g'(x)>0 and g"(x)>0 for all real numbers of x, such that g(4)=12 and g(5) = 18. Of the following, which is the possible value for g(6)?
g' > 0 for all x, so what does that tell you about the slope of g?

g'' > 0 for all x, so what does that tell you about the concavity of g?

I take it that this is a multiple choice problem, but you didn't include the possible answers in your problem description.
 
  • #3
If g'>0 and g">0 is the slope increasing and the concavity is upward? The choices are 15,18,21,24,27.
 
  • #4
MorganJ said:
If g'>0 and g">0 is the slope increasing and the concavity is upward?
Yes to both.
MorganJ said:
The choices are 15,18,21,24,27.

You know that g(4) = 12 and g(5) = 18. If the function happened to be a straight line, its slope would be (18 -12)/(5 -4) = 6, so in that case, g(6) would be 24.

The graph of g is not a straight line, since g'' > 0. This information eliminates all but one of the possible choices.
 

1. What is a twice-differentiable function?

A twice-differentiable function is a mathematical function that can be differentiated twice. This means that the function has a well-defined derivative at every point in its domain, and the derivative itself is also differentiable.

2. How is a twice-differentiable function different from a once-differentiable function?

A twice-differentiable function is different from a once-differentiable function in that it can be differentiated twice, while a once-differentiable function can only be differentiated once. This means that a twice-differentiable function has a smoother and more well-defined curve compared to a once-differentiable function.

3. What is the significance of a twice-differentiable function in real-life applications?

A twice-differentiable function is significant in real-life applications because it represents a function that is continuous and has a well-defined slope at every point. This makes it useful in modeling various phenomena in fields such as physics, economics, and engineering.

4. Can a twice-differentiable function have discontinuities?

No, a twice-differentiable function cannot have discontinuities. This is because a function must be continuous in order to be differentiable, and a twice-differentiable function must also have a continuous derivative. Discontinuities would result in undefined or infinite derivatives, which would violate the definition of a twice-differentiable function.

5. How can we determine if a function is twice-differentiable?

A function can be determined to be twice-differentiable by checking if it is continuously differentiable and if its derivative is also differentiable. This can be done by using the definition of differentiability, as well as various differentiation rules and techniques.

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