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sara_87
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Homework Statement
I have attached a picture including 2 equations: (2.13) and (2.14)
I don't understand how they got from (2.13) to (2.14) using integration by parts
Homework Equations
The Attempt at a Solution
For the integral:
[itex]\int_{\tau_0}^t\sigma(\tau)d\tau= \left[\sigma(\tau)\tau\right]_{\tau_0}^{t}-\int_{\tau_0}^t\dot{\sigma}(\tau)\tau d\tau[/itex]
by assuming [itex]u=\sigma(\tau)[/itex] and [itex]v'=1[/itex] for integration by parts.
This gives:
[itex]\sigma(t)t-\sigma(\tau_0)\tau_0-\int_{\tau_0}^{t}\tau\dot{\sigma}(\tau)d\tau[/itex]
So, even when we do combine this result with the other terms in equation (2.13), I don't understand how (2.14) does not depend on [itex]\sigma(t)[/itex].
Thank you in advance for any ideas.