Complex Integration: Solving $\int_0^1\frac{2t+i}{t^2+it^2+1}dt$

In summary, the conversation discusses the integral $\displaystyle\int_0^1\frac{2t+i}{t^2+it+1}dt$, with a possible typo in the denominator. After correcting the typo, it is determined that the integral is equal to $\ln\sqrt{5} + i\tan^{-1}\frac{1}{2}$.
  • #1
Dustinsfl
2,281
5
$\displaystyle\int_0^1\frac{2t+i}{t^2+it^2+1}dt = \int_0^1\frac{2t^3+3t+i-it^2}{t^4+3t^2+1}dt =\int_0^1\frac{2t^3+3t}{t^4+3t^2+1}dt+i\int_0^1 \frac{1-t^2}{t^4+3t^2+1}dt$

I tried multiplying through by the conjugate but that didn't seem fruitful and left me with the above expression. Is there a better way to tackle this problem?

Typo I mixed up two parts
 
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  • #2
dwsmith said:
$\displaystyle\int_0^1\frac{2t+i}{t^2+it^2+1}dt$
For a start, it looks as though there is a typo in the denominator. Shouldn't it be $\int_0^1\frac{2t+i}{t^2+it+1}dt$ ?

If so, the numerator is the derivative of the denominator, and the integral is
$\left[\ln(t^2+it+1)\right]_0^1 = \ln(2+i) = \sqrt5 + i\tan^{-1}\frac12$.
 
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  • #3
Opalg said:
For a start, it looks as though there is a typo in the denominator. Shouldn't it be $\int_0^1\frac{2t+i}{t^2+it+1}dt$ ?

If so, the numerator is the derivative of the denominator, and the integral is
$\left[\ln(t^2+it+1)\right]_0^1 = \ln(2+i) = \sqrt5 + i\tan^{-1}\frac12$.

Shouldn't that be $\ln\sqrt{5} + i\tan^{-1}\frac{1}{2}$?
 
  • #4
dwsmith said:
Shouldn't that be $\ln\sqrt{5} + i\tan^{-1}\frac{1}{2}$?
Yes! (Doh)
 

Related to Complex Integration: Solving $\int_0^1\frac{2t+i}{t^2+it^2+1}dt$

1. What is the purpose of complex integration?

Complex integration is used to calculate the area under a complex function curve. It is also used to solve complex differential equations and evaluate complex series.

2. How is complex integration different from real integration?

Complex integration involves integration over a complex plane, which takes into account both real and imaginary components. Real integration only involves integration over a real line.

3. What is the method for solving a complex integral?

The method for solving a complex integral involves breaking the complex function into simpler parts, using the properties of complex numbers, and then applying the fundamental theorem of calculus to evaluate the integral.

4. What is the significance of the limits of integration in complex integration?

The limits of integration represent the starting and ending points on the complex plane over which the integral is being evaluated. They affect the value of the integral and must be carefully chosen to accurately represent the area under the complex function curve.

5. How does complex integration relate to other branches of mathematics?

Complex integration is closely related to complex analysis, which is a branch of mathematics that deals with complex numbers and functions. It also has applications in physics, engineering, and other fields that involve complex systems and calculations.

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