Question

what is the integral of x sin x dx

Answer 1

Possible intermediate steps:
integral x sin(x) dx
For the integrand x sin(x), integrate by parts, integral f dg = f g- integral g df, where
f = x, dg = sin(x) dx,
df = dx, g = -cos(x):
= integral cos(x) dx-x cos(x)
The integral of cos(x) is sin(x):
= sin(x)-x cos(x)+constant

Answer 2

i found this explanation to be the most concise, as my explanation of the parts formula isn't too clear.

Answer 3

why is it concise? its standard

Answer 4

integral u dv = uv - integral v du

Answer 5

oh... right... nvm...

Answer 6

because i remember there was a way to do it by substitution...

Answer 7

not this one im afraid

Answer 8

:)

Answer 9

ok thanks. i learned something too.