Calculus help another one

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The correct answer is:∫ dx / (1 - x^2) = 1/2 ln |(1 + x) / (1 - x)| + CIn summary, the correct answer to the problem is 1/2 ln |(1 + x) / (1 - x)| + C.
  • #1
gigi9
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Calculus help please! another one

Can someone please show me how to show that this problem below is CORRECT? Thanks a lot.
Integral of dx/(1-x^2) = x/(1-x)
 
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Use the substitution x=sinu.
 
  • #3


Hello, gigi9!

The answer is not correct . . .

Originally posted by gigi9
Can someone please show me how to show that this problem below is CORRECT?
Integral of dx/(1-x^2) = x/(1-x)
We can use Partial Fractions: 1/(1 - x^2) = A/(1 - x) + B/(1 + x)
and find that: A = 1/2, B = -1/2.

The answer will be: (1/2) ln|(1 - x)/(1 + x)| + C
 
  • #4
Can someone please show me how to show that this problem below is CORRECT? Thanks a lot.
Integral of dx/(1-x^2) = x/(1-x)

The easiest way to check if an integral is correct is to invert the operation and differentiate.

Via the fundamental theorem of calculus, if

∫ dx / (1 - x^2) = x / (1 - x)

then

1 / (1 - x^2) = (d/dx) (x / (1 - x))

So if we actually perform the differentiation, we get:

1 / (1 - x^2) = 1 / (1 - x)^2

Because this equation is false, the original problem (as you've written it) must be false as well.
 

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Calculus is a branch of mathematics that deals with rates of change and accumulation of quantities. It is used to model and analyze dynamic systems in various fields such as physics, engineering, and economics.

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3. What are the two main branches of calculus?

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