- #1
jk22
- 729
- 24
The question is a bit confused, but it refers to if the following integration is correct :
$$I=\int \frac{1}{1+f'(x)}f'(x)dx$$
$$df=f'(x)dx$$
$$\Rightarrow I=\int\frac{1}{1+f'}df=?\frac{f}{1+f'}+C$$
The last equality would come if I suppose $f,f'$ are independent variables.
$$I=\int \frac{1}{1+f'(x)}f'(x)dx$$
$$df=f'(x)dx$$
$$\Rightarrow I=\int\frac{1}{1+f'}df=?\frac{f}{1+f'}+C$$
The last equality would come if I suppose $f,f'$ are independent variables.