When x
When x < At 0, there is ∫ (1/x) dx = ln (-x)+c; (x & lt0);
Therefore, regardless of x>0 or X.
In practice, the formula ∫( 1/x)dx=lnx+c is often used because it is simple and clear.
Just remember: x
Indefinite integral formula
1, ∫ a dx = ax+C, a and c are constants.
2. ∫ x a dx = [x (a+1)]/(a+1)+c, where a is a constant and a≦- 1.
3、∫ 1/x dx = ln|x| + C
4.∫ a x dx = (1/lna) a x+c, where a >;; 0 and a ≠ 1
5、∫ e^x dx = e^x + C
6、∫ cosx dx = sinx + C
7、∫ sinx dx = - cosx + C
8、∫ cotx dx = ln|sinx| + C = - ln|cscx| + C