Finding domain for when composite function is continuous

In summary, the conversation is about finding where the function ##h(x) = \ln(x^2)## is continuous on its entire domain. The reasoning behind this is that since the natural log is defined for positive values of x, the argument of the function, ##x^2##, must also be positive. Therefore, it can be determined that the function is not continuous at ##x=0##. The individual also asks for help in proving this by solving the equation. It is mentioned that the function is differentiable at all points except for ##x=0##. It is clarified that the function is actually written as ##\ln(x^2)## with a lowercase "l" instead of an uppercase "I".
  • #1
ChiralSuperfields
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Homework Statement
Please see below
Relevant Equations
Please see below
I am trying to find where ##h(x) =In{x^2}## is continuous on it's entire domain.

My reasoning is since natural log is defined for ##x > 0##, then the argument ##x^2## should be positive, ##x^2 > 0##, we can see without solving this equation that ##x ≠ 0## for this equation to be true, however, does someone please know how we could prove this by solving that equation for x?

My working is
##x > 0## (Taking square root of both sides of the equation)

Many thanks!
 
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  • #2
ChiralSuperfields said:
Homework Statement: Please see below
Relevant Equations: Please see below

I am trying to find where ##h(x) =In{x^2}## is continuous on it's entire domain.

My reasoning is since natural log is defined for ##x > 0##, then the argument ##x^2## should be positive, ##x^2 > 0##, we can see without solving this equation that ##x ≠ 0## for this equation to be true, however, does someone please know how we could prove this by solving that equation for x?

My working is
##x > 0## (Taking square root of both sides of the equation)

Many thanks!
It is neither defined nor continuous at ##x=0.## It is continuous everywhere else. What do you use to prove continuity? E.g. it is differentiable at ##x\neq 0## and therewith continuous. Or you use a definition for continuity. There are a few, so which one do you use?
 
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  • #3
ChiralSuperfields said:
I am trying to find where ##h(x) =In{x^2}## is continuous on it's entire domain.
There is no "##In()## function; i.e., starting with uppercase i. It's ##\ln()##, with a lowercase letter l (ell), short for logarithmus naturalis.
 
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  • #4
Note that [itex]\ln x^2 = 2\ln |x|[/itex].
 
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1. What is a composite function?

A composite function is a function that is formed by combining two or more functions. It is written as f(g(x)), where g(x) is the inner function and f(x) is the outer function.

2. How do I determine the domain for a composite function?

To determine the domain for a composite function, you must consider the domains of both the inner and outer functions. The domain of the composite function will be the set of all values that are in the domain of the inner function and produce a valid output in the domain of the outer function.

3. What is the importance of finding the domain for a composite function?

Finding the domain for a composite function is important because it ensures that the function is well-defined and has a valid output for all possible inputs. It also helps in identifying any restrictions on the inputs that may result in undefined values.

4. Can the domain of a composite function be different from the domains of its individual functions?

Yes, the domain of a composite function can be different from the domains of its individual functions. This can happen when the domains of the individual functions have overlapping values, but the composite function only has a subset of those values in its domain.

5. Are there any specific rules for finding the domain of a composite function?

Yes, there are some rules that can help in finding the domain of a composite function. These include avoiding division by zero, determining any restrictions on the inputs of the individual functions, and considering any limitations on the range of the inner function that may affect the domain of the composite function.

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