## theEric Group Title I used Wolfram Alpha to see that $$\int x^{-1} dx=\ln\left|x\right|+C$$, even though I don't understand why. But what about $$\int f(x)^{-1}dx$$? Wolfram Alpha couldn't come up with a formula. So, is this a problem when trying to solve with substitution? 11 months ago 11 months ago

1. Dido525 Group Title

That's basically the integral of 1/f(x) . There are many possibilities depending on what f(x) is.

2. Dido525 Group Title

you may have to use techniques other than substitution possibly.

3. Dido525 Group Title

For instance if f(x) is 1+x^2 than we have the integral of 1/(1+x^2) which is arctan(x) + c

4. dan815 Group Title

|dw:1377755678612:dw|

5. theEric Group Title

Okay! So, if the function is know, then we just try to integrate it. Thank you!

6. theEric Group Title

I'm going to ask about the specific problem in another post. This one is done, thanks! :)

7. Dido525 Group Title

Allright :) .