is a french first group verb. So it follow the regular conjugation pattern of the first group like: aimer
Follow this link to see all the endings of the conjugation of the first group verbs : conjugation rules and endings for the first group verbs
Diagnostiquer is conjugated the same way that verbs that end in : -er
First group verbs always end with -er
as their infinitive. Endings of first group verbs are regular.
Note : Although endings are perfectly regular, spelling changes occur in the stems of verbs in -cer
, verb envoyer
and similar verbs.