楽しい and 面白い: enjoyable experiences and interesting subjects
Compare enjoyment in an experience with interest in a subject, and recognize that 面白い does not always mean funny.
Enjoy an experience
友達と過ごした週末は楽しかったです。 says that the weekend spent with friends was enjoyable. 楽しい, read たのしい, expresses enjoyment in experiencing that time.
楽しい旅行でした。 describes an enjoyable trip. It does not assert that every moment involved laughter or that there were no inconveniences.
Distinguish interest from humor
この歴史の本は面白いです。 can mean that this history book is interesting. 面白い, read おもしろい, also describes engaging content, not only a funny book.
彼の冗談は面白くて、みんな笑いました。 says that his joke was funny and everyone laughed. 冗談 and 笑う make the humorous sense clear here.
Two perspectives on one activity
授業は面白かったし、友達と話せて楽しかったです。 says that the class was interesting, and the speaker was happy to be able to talk with friends. Interest in the content and enjoyment of the experience can coexist.
楽しく話しました describes talking enjoyably; 面白い話を聞きました describes hearing an interesting or amusing story. Identify whether the evaluation concerns the activity or its content.
Must 面白い歴史の本 be a funny history book?
Show the answer and why
No. It can mean a history book with interesting content. Context distinguishes humor from intellectual interest.