Hello fouadissam,

You can connect to the AP with a console cable and enter show ip interface brief, which will display the ip address.
 
If its connected to a network you can log into your switch and enter show arp | i xxxx.xxxx.xxxx(mac address of the AP).
 
The below link points to a configuration guide that may be helpful.

http://www.cisco.com/c/dam/en/us/td/docs/wireless/access_point/15_2_4_JB/configuration/guide/scg15_2_4_JB3a.pdf

Hope this helps,
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Thanks.