It is difficult to remember the formula of physics or the reaction of chemistry. What can I do ? প্রমাণ You need to know the evidence of these sources well. We all know ( a + b) 2 = a2 + 2ab + b2 by heart . But , how many can prove it ? In fact , if you know the evidence of the sources, you can find a way out even if you forget them. And , when giving traditional advice, you have to write down the difficult formulas and reactions on a piece of paper and put it in front of the table. The subconscious mind remembers things more. You can read these articles!