# Integration limits

1. Feb 22, 2014

### Miraj Kayastha

is the upper limit always greater than the lower limit in integration?

what should be the limits if we need to calculate total work done in bringing a mass from infinity to distance r from earth.

2. Feb 22, 2014

### pwsnafu

$\int_a^b f(x) \, dx = - \int_b^a f(x) \, dx$.

3. Feb 22, 2014

### PhysicoRaj

$\int$r

4. Mar 11, 2014

### Boson

There is decrease in potential energy of system. So, negative work is done. -{infinity to r}