Calculating gain on Op Amp with AC voltage
A simple procedure when calculating AC versus DC gain is to consider all the capacitors open for the DC case and shorts for the AC case.  Then you can look more closely and see what resistance are accross or in series with the capacitors and use the formula:

&nbsp;&nbsp;F = 1 / (2&pi;RC)

to see at what frequency the high pass or low pass rolloff is at.  When R is in Ohms, C in Farads, then F is in Hertz.

From the above, it should be pretty obvious that the DC gain is 10, and the AC gain at high frequencies is 1.  Now, can you tell us what the rolloff frequency of this low pass filter is?