How do you integrate int x^(1/2)*ln(x) using integration by parts?

1 Answer
Nov 29, 2015

2/9 x^[3/2)(3ln(x)-2) +C

Explanation:

Integration by part :
intf(x)g'(x)dx = f(x)g(x)-intf'(x)g(x)dx

Given int root()x*ln(x)dx

Let f(x)= lnx
color(blue)(f'(x)= 1/x dx " " " " " "(1)

Let g'(x)= x^(1/2)dx hArr g(x) = int x^(1/2)dx =>color(red)( g(x)= 2/3 x^(3/2) " " " " " " (2)

int root()x*ln(x)dx = color(red)(2/3 x^(3/2))*ln(x)- intcolor(red)( " " 2/3 x^(3/2)*color(blue)((1/x)dx)

2/3 x^(3/2) ln(x) - 2/3 intx^(1/2)dx

2/3 x^(3/2) ln(x) - 2/3*2/3(x^(3/2)) + C

2/3 x^(3/2) ln(x) - 4/9(x^(3/2)) + C

Can be simplify to
2/9 x^[3/2)(3ln(x)-2) +C