Math Problem Statement

Evaluate the integral: -ln(2) ∫ 2e^θ cosh(θ) dθ - ln(6)

Solution

The given image represents a definite integral expression:

ln2eθ2cosh(θ)dθln6-\ln 2 \int e^\theta 2 \cosh(\theta) \, d\theta - \ln 6

To solve this, let's break it down step-by-step:

1. First, consider the integral part:

I=2eθcosh(θ)dθI = \int 2 e^\theta \cosh(\theta) \, d\theta

Recall that:

cosh(θ)=eθ+eθ2\cosh(\theta) = \frac{e^\theta + e^{-\theta}}{2}

Substitute this into the integral:

I=2eθ(eθ+eθ2)dθI = \int 2 e^\theta \left( \frac{e^\theta + e^{-\theta}}{2} \right) \, d\theta

Simplify:

I=eθ(eθ+eθ)dθI = \int e^\theta (e^\theta + e^{-\theta}) \, d\theta

Now distribute:

I=e2θdθ+1dθI = \int e^{2\theta} \, d\theta + \int 1 \, d\theta

Solve each part:

  • The first integral is:

e2θdθ=e2θ2\int e^{2\theta} \, d\theta = \frac{e^{2\theta}}{2}

  • The second integral is simply:

1dθ=θ\int 1 \, d\theta = \theta

Thus, the result of the integral is:

I=e2θ2+θ+CI = \frac{e^{2\theta}}{2} + \theta + C

2. Next, return to the full expression:

ln2(e2θ2+θ)ln6-\ln 2 \left( \frac{e^{2\theta}}{2} + \theta \right) - \ln 6

Distribute ln2-\ln 2:

ln2e2θ2ln2θln6-\ln 2 \cdot \frac{e^{2\theta}}{2} - \ln 2 \cdot \theta - \ln 6

So, the final result is:

ln22e2θln2θln6+C-\frac{\ln 2}{2} e^{2\theta} - \ln 2 \cdot \theta - \ln 6 + C

Would you like further details or clarification?

Relative questions:

  1. What is the meaning of the hyperbolic cosine function cosh(θ)\cosh(\theta) and how is it derived?
  2. How do we compute definite integrals when there are logarithmic coefficients?
  3. How does the distribution of constants work in integration problems?
  4. What are some practical applications of the hyperbolic cosine function in physics or engineering?
  5. Why is understanding substitution methods essential for solving integrals?

Tip:

When dealing with integrals of exponential and hyperbolic functions, always try to rewrite them in simpler forms like exponentials to make the integration more straightforward.

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Math Problem Analysis

Mathematical Concepts

Integral Calculus
Hyperbolic Functions
Exponential Functions

Formulas

cosh(θ) = (e^θ + e^(-θ)) / 2
∫ e^2θ dθ = (e^2θ) / 2
∫ 1 dθ = θ

Theorems

Fundamental Theorem of Calculus
Properties of Hyperbolic Functions

Suitable Grade Level

College Level - Calculus