Can a 5th gen iPad be used with a first gen apple pen

Sorry, no

Compatible with

• iPad (6th, 7th, and 8th generation)
• iPad Air (3rd generation) 
• iPad mini (5th generation) 
• iPad Pro 12.9-inch (1st and 2nd generation)
• iPad Pro 10.5-inch
• iPad Pro 9.7-inch

BUt there are other styli that can be used. Wacom has some as well as Adonit. Michael will probably be along with a comprehensive list of apps and styli that he recommends.

Sorry, no.