Write a logical function isguest to determine if a name is on the guest list of an event. the function should operate independent of upper or lower case characters in the string. a string array contains the guest list. if there are multiple entries of the same name, a single logical must be returned.

Precipitation hardening can be achieved in many light alloys by a three-step heat treatment. what is carried out and what is the purpose at each step? why is such a treatment necessary based on the nucleation and growth theory of phase transformation. compare this treatment with tempering martensite for carbon steels (similarities and differences).