Reduction formulaHardQuestion 330009
Question
∫ln x dx equals:
- Ax ln x − x + CCorrect
- Bln x + C
- Cx/ln x + C
- Dln x / x + C
Correct answer
x ln x − x + C
Explanation
By parts: u = ln x, dv = dx → du = 1/x dx, v = x. ∫ln x dx = x ln x − ∫x·(1/x) dx = x ln x − ∫1 dx = x ln x − x + C.