The question was the following:
What's the difference between the simple future tense and the future progressive tense?
Simple future tense: "I will leave tomorrow."
Future progressive tense: "I will be leaving tomorrow."
Do they have the same meaning?
If you simply want to state that the action will happen in the future, you can use the simple present.
This tense gives no other data than the time --> FUTURE.
"I don't have time to study today, but I will study tomorrow."
This sentence simply tells you that the action (studying) will happen in the future.
The future progressive, however, tells you two things.
1) It tells you the time of the action --> FUTURE.
2) It tells you that the action will be IN PROGRESS.
"Tomorrow at nine o'clock I will be studying, so don't call me."
This sentence tells you that the action (studying) will be IN PROGRESS at nine o'clock.
In conclusion, if you simply would like to say that the action will happen, you can use the simple future tense.
If you would like to say that the action will happen, and you want to emphasize that it will be in progress at that time, you can use the future progressive tense.
So "I will leave tomorrow" and "I will be leaving tomorrow" do have very similar meanings. However, the second one puts emphasis on the continuation of the action.