Question

name 3 important baroque composers.

Answer 1

As the Baroque period began around 1600 and Malcolm's suggestions are all from the middle and late Baroque periods, I would add some names for some of the most important composers:

Early Baroque:
Girolamo Frescobaldi
Claudio Monteverdi
Heinrich Schütz

Middle Baroque:
Jean-Baptiste Lully
Marc-Antoine Charpentier

Late Baroque:
François Couperin