# how to integrate ln(x)

by ekinnike
Tags: integrate
 P: 27 i cant find it anywhere. plz help. i need to kno the inegration of lnx to find an area. plz help thx
 HW Helper P: 1,422 Integration is a Calculus topic, and therefore, should not be posted in the Precalculus section. Anyway, to integrate ln(x), we use Integration by Parts (have you covered Integration by Parts yet?), i.e: $$\int u dv = uv - \int v du$$ We often use Integration by Parts, when no other methods can solve the integral. So, we want to integrate this: $$\int \ln (x) dx$$ We then let u = ln(x), and dv = dx So that implies du = dx / x, and v = x. Substitute all those into the formula, we have: $$\int \ln (x) dx = x \ln (x) - \int x \times \frac{dx}{x} = ...$$ Can you go from here? :)
P: 27
 Quote by VietDao29 Integration is a Calculus topic, and therefore, should not be posted in the Precalculus section. Anyway, to integrate ln(x), we use Integration by Parts (have you covered Integration by Parts yet?), i.e: $$\int u dv = uv - \int v du$$ We often use Integration by Parts, when no other methods can solve the integral. So, we want to integrate this: $$\int \ln (x) dx$$ We then let u = ln(x), and dv = dx So that implies du = dx / x, and v = x. Substitute all those into the formula, we have: $$\int \ln (x) dx = x \ln (x) - \int x \times \frac{dx}{x} = ...$$ Can you go from here? :)
lol i didnt learn those yet. BUt im glad it more complicated than it look. NO i cant do it. BUt i really appriciated the help. Instead i will try use simpsons rule. the question is area under the curve. 2day is monday-im at school school today so i quickly ask one of the mathematics teacher. =) i think he also hesitated say u can solve them by harder way but instead he told me simpson rule