I found this circuit in [here][1]. I know that it's a multi-stage cascaded BJT Amplifier and I know how to calculate it. 

My question is, what R8 is used for? And If I remove it, is it cause any problem or bad effect. Thank you guys so much

[![enter image description here][2]][2]


  [1]: http://www.dientuvietnam.net/forums/forum/h%E1%BB%8Dc-t%E1%BA%ADp-nghi%C3%AAn-c%E1%BB%A9u-%C4%90%E1%BB%93-%C3%A1n-%C4%90%E1%BB%81-t%C3%A0i-d%E1%BB%B1-%C3%A1n/h%E1%BB%97-tr%E1%BB%A3-h%E1%BB%8Dc-t%E1%BA%ADp/179421-xin-h%E1%BB%8Fi-v%E1%BB%81-m%E1%BA%A1ch-khu%E1%BA%BFch-%C4%91%E1%BA%A1i-t%C3%ADn-hi%E1%BB%87u-nh%E1%BB%8F-d%C3%B9ng-bjt
  [2]: https://i.sstatic.net/slmNT.png