What is a differential??? I have a strange problem. I am supose to enter a physics cometition in about 2 months, where the knowledg of differential equations is almost necasery, but we haven't done yet any at our mathemathics or physics class. Our mathemathics teacher doesn't wan't to explein them to me and the books we are useing also have almost no explination. I would be very happy if someone could plees explain the basics. Thanks.