Is the future tense of broadcast will be broadcasted?

Answer 1

"Broadcast" is the agglutinated ("stuck together") form of "broad" plus "cast", meaning "thrown abroad", as in sowing grain.

Accordingly its past tense and past participle are as in "cast", which remains unchanged, as in: "Watch him cast seed abroad the way I cast the discus yesterday" or as the participle: "This iron that I cast while it was molten has now hardened into cast iron."

Compare these with: "Watch him throw seed abroad the way I threw the discus yesterday" or as the participle: "This iron that I poured into the mould while it was molten has now hardened into moulded iron." (If you are American, you would spell that "mold".)

Similarly: "The message that I shouted or broadcast from the stage yesterday has now also been heard in the publicised or broadcast news on the radio."

However, rules have become less strict, and nowadays in common usage the past participle sometimes is written with an added "-ed": "the broadcasted news on the radio." I don't recommend it, but some dictionaries do accept the usage.

In "...will be broadcast..." the "broadcasted" or "broadcast" is the participle form, so the preferred form is "broadcast", but as I said, some dictionaries accept it. Mind you, some will accept practically anything...