integration question (1 Viewer)

F

fuckit1991

Guest
hey got a integration by sub question.
using the substitution x=pi - y , evalute integrand(xsin^3(x)) dx from pi to 0.
(the integral is read x multiplied by sine cubed x)

i get up to (pi-y)sin^3(y) dy but not sure of where to go form there

TIA
 

Timothy.Siu

Prophet 9
Joined
Aug 6, 2008
Messages
3,449
Location
Sydney
Gender
Male
HSC
2009
hey got a integration by sub question.
using the substitution x=pi - y , evalute integrand(xsin^3(x)) dx from pi to 0.
(the integral is read x multiplied by sine cubed x)

i get up to (pi-y)sin^3(y) dy but not sure of where to go form there

TIA
split it and add it back,

split it to pisin^3(y) -ysin^3(y)
u can add the ysin^3(y) to the other side...and keep going
 

Drongoski

Well-Known Member
Joined
Feb 22, 2009
Messages
4,255
Gender
Male
HSC
N/A
hey got a integration by sub question.
using the substitution x=pi - y , evalute integrand(xsin^3(x)) dx from pi to 0.
(the integral is read x multiplied by sine cubed x)

i get up to (pi-y)sin^3(y) dy but not sure of where to go form there

TIA
Is the answer 2pi/3 ?? If so I'll post solution.
 
Last edited:
F

fuckit1991

Guest
the answer is 2pi/3 sorry for not including it earlier. ah i see what trebla is saying about the dummy variables...wasn't aware of this 'idea' so the question kinda stumped me... thanks to everyone who helped...appreciate it tons :D
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top