Math Problem Statement

lim(x->0+) x^sqrt(x)

Solution

To find limx0+xx\lim_{x \to 0^+} x^{\sqrt{x}}, let's analyze the behavior of the function carefully.

Step 1: Rewrite the function

We can express xxx^{\sqrt{x}} as an exponential: xx=eln(xx)=exln(x).x^{\sqrt{x}} = e^{\ln(x^{\sqrt{x}})} = e^{\sqrt{x} \ln(x)}.

So, we now focus on evaluating the limit of the exponent xln(x)\sqrt{x} \ln(x) as x0+x \to 0^+.


Step 2: Analyze xln(x)\sqrt{x} \ln(x)

Substitute t=xt = \sqrt{x}, so t2=xt^2 = x. As x0+x \to 0^+, we have t0+t \to 0^+. Thus: xln(x)=tln(t2).\sqrt{x} \ln(x) = t \ln(t^2). Using the property of logarithms, ln(t2)=2ln(t)\ln(t^2) = 2\ln(t), so: tln(t2)=t2ln(t)=2tln(t).t \ln(t^2) = t \cdot 2\ln(t) = 2t \ln(t).

Now we analyze the behavior of 2tln(t)2t \ln(t) as t0+t \to 0^+:

  • ln(t)\ln(t) \to -\infty as t0+t \to 0^+,
  • t0+t \to 0^+ approaches 0.

Thus, the term tln(t)t \ln(t) is an indeterminate form 0()0 \cdot (-\infty), and we use substitution or L'Hôpital's Rule to evaluate it.


Step 3: Use substitution

Let u=ln(t)u = \ln(t), so t=eut = e^u and uu \to -\infty as t0+t \to 0^+. Then: tln(t)=euu.t \ln(t) = e^u \cdot u. As uu \to -\infty, eu0e^u \to 0 faster than uu \to -\infty. Thus: euu0.e^u \cdot u \to 0.

Therefore: xln(x)0asx0+.\sqrt{x} \ln(x) \to 0 \quad \text{as} \quad x \to 0^+.


Step 4: Conclude the result

Since xln(x)0\sqrt{x} \ln(x) \to 0, we have: xx=exln(x)e0=1.x^{\sqrt{x}} = e^{\sqrt{x} \ln(x)} \to e^0 = 1.

Thus, the limit is: limx0+xx=1.\lim_{x \to 0^+} x^{\sqrt{x}} = 1.


Final Answer:

1\boxed{1}

Would you like a deeper explanation of any step? Here are some related questions to expand your understanding:

  1. What is the general behavior of xax^a as x0+x \to 0^+ for different values of aa?
  2. How does L'Hôpital's Rule help in evaluating indeterminate forms like 0()0 \cdot (-\infty)?
  3. What is the significance of logarithmic transformations in limit problems?
  4. Can limx0xx\lim_{x \to 0^-} x^{\sqrt{x}} be evaluated, and if so, what is the result?
  5. How would the limit change if xxx^{\sqrt{x}} was replaced by xxpx^{x^p} for some p>0p > 0?

Tip: Transforming problems into exponential and logarithmic forms often simplifies limit evaluations significantly.

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Math Problem Analysis

Mathematical Concepts

Limits
Exponential Functions
Logarithmic Transformations
Indeterminate Forms

Formulas

x^a = e^{a * ln(x)}
L'Hôpital's Rule
Logarithmic Property: ln(t^2) = 2 * ln(t)

Theorems

L'Hôpital's Rule
Properties of Exponential and Logarithmic Limits

Suitable Grade Level

Undergraduate Mathematics or Advanced High School Calculus