The more informal way to say "I will study a lot tomorrow" in Spanish is "Estudiaré mucho mañana." However, if you're looking to express it even more informally, you might say something like "Mañana estudiaré un montón." or "Mañana voy a estudiar un chingo.", depending on the region and the level of informality you're comfortable with.
From the options you provided, none are fully correct, but here's a short correction:
- "Estudio mucho mañana." would be more like "I study a lot tomorrow."
For a casual tone, you could say:
- "Mañana estudio mucho." (Tomorrow I’ll study a lot.)
Let me know if you need more help!