- #1
falcao
- 9
- 0
Just working through a problem Acheson's book (From Calculus to Chaos) if anyone knows it.. eq 8.6 in this book..
As he's working through the problem he makes the step of this:
[tex]
m\int_{t_{1} }^{t_{2}} \left( \dot{y}_{\scriptscriptstyle A }\dot{\eta} - g\eta \right)\,dt
[/tex] (1)
to
[tex]m\left[\dot{y}_{\scriptscriptstyle A} \eta\right]_{t_{1}}^{t_{2}} -
m\int_{t_{1}}^{t_{2}}\left(\ddot{y}_{\scriptscriptstyle A} + g\right)\eta\,dt
[/tex] (2)
... using integration by parts.
Now, I've been stuck on it for a little while and I can't really figure it out.. I tried 'taking out' the [tex]\eta[/tex] but had no luck, if anyone had any suggestions of what to let == dv and what to let == u in the formula it would probably sort me out!
[tex]\int u\,dv = uv - \int v\,du
[/tex]
Thanks in advance! (ps. I can post further workings if necessary)
As he's working through the problem he makes the step of this:
[tex]
m\int_{t_{1} }^{t_{2}} \left( \dot{y}_{\scriptscriptstyle A }\dot{\eta} - g\eta \right)\,dt
[/tex] (1)
to
[tex]m\left[\dot{y}_{\scriptscriptstyle A} \eta\right]_{t_{1}}^{t_{2}} -
m\int_{t_{1}}^{t_{2}}\left(\ddot{y}_{\scriptscriptstyle A} + g\right)\eta\,dt
[/tex] (2)
... using integration by parts.
Now, I've been stuck on it for a little while and I can't really figure it out.. I tried 'taking out' the [tex]\eta[/tex] but had no luck, if anyone had any suggestions of what to let == dv and what to let == u in the formula it would probably sort me out!
[tex]\int u\,dv = uv - \int v\,du
[/tex]
Thanks in advance! (ps. I can post further workings if necessary)