Sometime even after you install the SQL Reporting Services in SharePoint Mode to the Application Server you might get the below error
Install-SPRSService : The term ‘Install-SPRSService’ is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
The reason might be the wrong version of SQL 2012 Reporting Services for SharePoint is installed. For SharePoint 2013 SQL 2012 SP1 is the requirement. In some cases if you have downloaded the SQL 2012 SP1 installer during November 2012 or before there is an issue with Microsoft Site that the SP1 will not be installed. So please download the latest SQL 2012 SP1 installer ISO and install the Reporting Service in SharePoint Mode.
Installing the SP1 with the latest ISO will solve the issue.