How Challenging Is This Definite Integral with a Tangent and Pi Power?

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SUMMARY

The integral $$\int_0^{\frac{\pi}{2}} \frac{dx}{1+(\tan x)^{\pi e}}$$ presents a challenging evaluation due to the combination of the tangent function and the exponent involving Pi and Euler's number. MarkFL provided a correct solution, confirming the complexity of the integral. The discussion highlights the importance of understanding trigonometric functions and their properties in calculus.

PREREQUISITES
  • Understanding of definite integrals
  • Knowledge of trigonometric functions, specifically tangent
  • Familiarity with Pi (π) and Euler's number (e)
  • Basic calculus techniques for evaluating integrals
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  • Study advanced techniques for evaluating definite integrals
  • Explore properties of trigonometric functions in calculus
  • Learn about the applications of Pi and e in mathematical analysis
  • Investigate numerical methods for approximating complex integrals
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Mathematics students, calculus instructors, and anyone interested in advanced integral evaluation techniques will benefit from this discussion.

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Evaluate $$\int_0^{\frac{\pi}{2}} \frac{dx}{1+(\tan x)^{\pi e}}$$.
 
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Here is my solution:

We are given to evaluate:

$$I=\int_0^{\frac{\pi}{2}}\frac{1}{1+\tan^{\pi e}(x)}\,dx$$

Using the property of definite integrals $$\int_0^a f(x)\,dx=\int_0^a f(a-x)\,dx$$ and a co-function identity, we may state:

$$I=\int_0^{\frac{\pi}{2}}\frac{1}{1+\cot^{\pi e}(x)}\,dx$$

Adding the two equations, we obtain:

$$2I=\int_0^{\frac{\pi}{2}}\frac{1}{1+\tan^{\pi e}(x)}+\frac{1}{1+\cot^{\pi e}(x)}\,dx$$

$$2I=\int_0^{\frac{\pi}{2}}\frac{2+\tan^{\pi e}(x)+\cot^{\pi e}(x)}{2+\tan^{\pi e}(x)+\cot^{\pi e}(x)}\,dx=\int_0^{\frac{\pi}{2}}\,dx=\frac{\pi}{2}$$

Hence:

$$I=\frac{\pi}{4}$$
 
MarkFL said:
Here is my solution:

We are given to evaluate:

$$I=\int_0^{\frac{\pi}{2}}\frac{1}{1+\tan^{\pi e}(x)}\,dx$$

Using the property of definite integrals $$\int_0^a f(x)\,dx=\int_0^a f(a-x)\,dx$$ and a co-function identity, we may state:

$$I=\int_0^{\frac{\pi}{2}}\frac{1}{1+\cot^{\pi e}(x)}\,dx$$

Adding the two equations, we obtain:

$$2I=\int_0^{\frac{\pi}{2}}\frac{1}{1+\tan^{\pi e}(x)}+\frac{1}{1+\cot^{\pi e}(x)}\,dx$$

$$2I=\int_0^{\frac{\pi}{2}}\frac{2+\tan^{\pi e}(x)+\cot^{\pi e}(x)}{2+\tan^{\pi e}(x)+\cot^{\pi e}(x)}\,dx=\int_0^{\frac{\pi}{2}}\,dx=\frac{\pi}{2}$$

Hence:

$$I=\frac{\pi}{4}$$

Well done, MarkFL!(Clapping) Your answer is spot on!
 

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