Math Problem Statement

Реши

Determine if the given improper integrals converge or diverge: 1. \( \int_0^1 \frac{e^{x^2} - 1}{\sqrt{\tan{\sqrt{x}}}} \, dx \) 2. \( \int_0^1 \frac{\sin^2{x}}{x^3} \, dx \) 3. \( \int_0^1 \frac{e^{\sqrt{x}} - 1}{x} \, dx \)

Solution

Let us analyze the given integrals and determine whether they converge or diverge:

Integrals:

  1. 01ex21tanxdx\int_0^1 \frac{e^{x^2} - 1}{\sqrt{\tan{\sqrt{x}}}} \, dx
  2. 01sin2xx3dx\int_0^1 \frac{\sin^2{x}}{x^3} \, dx
  3. 01ex1xdx\int_0^1 \frac{e^{\sqrt{x}} - 1}{x} \, dx

We will evaluate the behavior of each integral at the given bounds.


Step 1: Analyze 01ex21tanxdx\int_0^1 \frac{e^{x^2} - 1}{\sqrt{\tan{\sqrt{x}}}} \, dx

  • As x0+x \to 0^+:

    • The numerator ex21x2e^{x^2} - 1 \approx x^2 (using Taylor expansion of ex2e^{x^2}).
    • The denominator tanx\sqrt{\tan{\sqrt{x}}} approximates x=x1/4\sqrt{\sqrt{x}} = x^{1/4}.
    • The integrand behaves like x2x1/4=x7/4\frac{x^2}{x^{1/4}} = x^{7/4}, which is integrable at 0.
  • As x1x \to 1^-:

    • Both ex21e^{x^2} - 1 and tanx\tan{\sqrt{x}} are finite. The integrand remains finite.

Conclusion: This integral converges.


Step 2: Analyze 01sin2xx3dx\int_0^1 \frac{\sin^2{x}}{x^3} \, dx

  • As x0+x \to 0^+:
    • The numerator sin2xx2\sin^2{x} \sim x^2 (using sinxx\sin{x} \approx x).
    • The denominator x3x^3 dominates x2x^2, and the integrand behaves like x2x3=1x\frac{x^2}{x^3} = \frac{1}{x}, which is not integrable at 0 (diverges as lnx\ln{x}).

Conclusion: This integral diverges.


Step 3: Analyze 01ex1xdx\int_0^1 \frac{e^{\sqrt{x}} - 1}{x} \, dx

  • As x0+x \to 0^+:
    • The numerator ex1xe^{\sqrt{x}} - 1 \approx \sqrt{x} (using Taylor expansion of exe^{\sqrt{x}}).
    • The denominator xx dominates x\sqrt{x}, and the integrand behaves like xx=1x\frac{\sqrt{x}}{x} = \frac{1}{\sqrt{x}}, which is not integrable at 0.

Conclusion: This integral diverges.


Final Answers:

  1. 01ex21tanxdx\int_0^1 \frac{e^{x^2} - 1}{\sqrt{\tan{\sqrt{x}}}} \, dxConverges.
  2. 01sin2xx3dx\int_0^1 \frac{\sin^2{x}}{x^3} \, dxDiverges.
  3. 01ex1xdx\int_0^1 \frac{e^{\sqrt{x}} - 1}{x} \, dxDiverges.

Would you like further explanations or steps for any specific case?

Related Questions:

  1. What is the mathematical concept of convergence for improper integrals?
  2. How can Taylor expansions help analyze limits of functions?
  3. How does the behavior near singular points affect integrals?
  4. What are the key differences between convergent and divergent integrals?
  5. How can substitution simplify the evaluation of improper integrals?

Tip:

Always check the behavior of the integrand at critical points (like x0x \to 0 or xx \to \infty) to determine convergence.

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Math Problem Analysis

Mathematical Concepts

Improper Integrals
Taylor Expansion
Behavior of Functions near Singularities

Formulas

Taylor expansion for exponential functions
Behavior of sine function for small x (sin(x) ≈ x)

Theorems

Convergence of improper integrals at singular points

Suitable Grade Level

Undergraduate level calculus or AP Calculus BC