In the circle of WeChat friends, people often turn to "the line between two points is not the shortest", which is misleading. Friends who have seen it must firmly believe that the straight line distance between two points is the shortest. Only in the curve between two points, the straight line is not the shortest descent curve (steepest descent line). The fascinating story of "steepest descent line" can be traced back to 1696.

1696 In June, johann bernoulli published a challenging question in Teacher's Magazine. Given two points A and B, one is high and the other is low (not on a vertical line, of course), it takes the shortest time for a ball to roll from point A to point B to find the curve between the two points. The answer is scheduled for 1697 65438+ 10/0/announcement.

Unfortunately, until the deadline, he only received a letter from the great Leibniz, without giving an answer, but asked to extend the solution period to Easter, so that no one would complain that the time was too short when the answer was published. Proud Bernoulli personally announced the extension of the deadline, copied the title and sent a copy to the great Newton to ensure that Newton knew the challenge.

At the end of Easter, Bernoulli received five replies from himself, Leibniz, Jacob Bernoulli (John's brother) and Roberta, including an anonymous email from Cambridge, England. This really depressed Bernoulli for a long time, because the answer is correct, no doubt from the hands of a super genius. Bernoulli finally admitted: "I recognized the lion (Newton! )。 "

The story comes from a genius-directed course, and the original text is more detailed and wonderful. Recommend this book!