It is 1636 and you are interested in buying tulips as an investment. As part of your research, you monitor the price of tulips for ten consecutive weeks and find that the price increases, each week by a greater amount than it did in the last. You decide that the price of tulips is on an upwards trend. Therefore, you can buy tulips now and sell them for more money before the price goes down. Just before you place the trade, a time traveller who is well versed in calculus, appears and gives you advice on the trade. What do they tell you about your plan?