The `` d '' differential goes '' 1 + i `` down and '' 2 + i `` on the right . The differential `` d '' goes `` 1 + i '' down and `` 2 + i '' right .
Pembezaan "d" 'berlaku'' 1 + i `bawah dan'' 2 + i `di sebelah kanan. Pembezaan "d" 'ke bawah "1 +i'' dan "2 +i'' betul.