At the time I write this, there are a lot of people getting into Bitcoin mining for the first time. Many buy ASIC hardware and are later surprised that their mining income suddenly drops due to a difficulty increase.
If I mine
X bitcoins per day, then the difficulty goes up
Y percent, how many coins do I get per day after this?
For instance, if my hashrate brings 1 BTC per day and the difficulty rises 30%, what is my average daily mining income with the same hashrate after this change in difficulty?