Why is the Constant 1/2 Used in Evaluating Integrals and Differentials?

In summary, the conversation discusses the equation \int\frac{x}{x^2+1} = \frac{1}{2}ln(x^2+1) and how the one half in the right hand side comes from the chain rule. The conversation also suggests using a u-substitution to evaluate the integral and emphasizes the importance of understanding the fundamentals of taking derivatives.
  • #1
fiziksfun
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Can someone explain to me why [tex]\int\frac{x}{x^2+1}[/tex] = [tex]\frac{1}{2}[/tex]ln(x^2+1) WHERE DOES THE ONE HALF COME FROM ?
 
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  • #2


Take the derivative of the right hand side and find out for yourself. (Hint: Chain rule.)
 
  • #3


[tex](ln(u))' = \frac{u'}{u}[/tex]
 
  • #4


ok none of these responses helped me at all.
 
  • #5


Did you take the derivative of the right hand side?
 
  • #6


You can also evaluate the LHS i.e. the integral

Hint #1 - it's a u-subst.

Hint #2 - let u = x^2 + 1
 
  • #7


I'm sorry but the OP has no business trying a u-sub if he doesn't follow the first hint. The idea that you can take the derivative to verify the correctness of an integral is fundamental. Remembering to apply the chain rule answers the question. I mean sure, he could apply a technique that really follows from these basic principles but then it would be hard to tell if he actually knew why.
 

FAQ: Why is the Constant 1/2 Used in Evaluating Integrals and Differentials?

What is the difference between integrals and differentials?

Integrals and differentials are both mathematical concepts used to calculate and analyze functions. Integrals measure the area under a curve, while differentials measure the rate of change of a function at a specific point. In other words, integrals give the total value of a function over a certain interval, while differentials give the instantaneous change of the function at a specific point.

How are integrals and differentials related?

Integrals and differentials are related through the Fundamental Theorem of Calculus. This theorem states that the integral of a function can be found by evaluating its antiderivative, which is the function that, when differentiated, gives the original function. In other words, the integral and the derivative of a function are inverse operations.

What is the purpose of using integrals and differentials?

Integrals and differentials are used to solve a variety of problems in mathematics, physics, engineering, and other fields. They are essential tools in calculating areas, volumes, and rates of change, as well as in analyzing and modeling real-world phenomena.

How do I solve integrals and differentials?

The process of solving integrals and differentials involves finding the antiderivative of a function and then evaluating it at specific points or over a certain interval. This can be done using various integration techniques, such as substitution, integration by parts, and partial fraction decomposition. Additionally, integrating and differentiating are skills that require practice and familiarity with mathematical concepts.

Can integrals and differentials be used to solve real-world problems?

Yes, integrals and differentials are widely used in various fields to solve real-world problems. For example, they can be used to calculate the area under a demand curve in economics, the velocity of a moving object in physics, or the growth rate of a population in biology. They are powerful tools for analyzing and understanding complex systems and phenomena in the world around us.

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