**I really appreciate you guys' time and advice!**## my math world

As a loyal audience, the most joyful time in middle-school was turning on the TV on time to watch the latest episode of Detective Conan. After the theme song, a gloomy door would open, marking the start of a new story and my brand-new math world.

Math in middle school was only about math. While I did enjoy the process of determining the chord lengths or proving Vieta's theorem, I doubted its practicality in life. Even subtraction and addition learned in primary school were far more useful. But I saw this little detective boy, interpreting the evidence from perspectives of various subjects: math, physics, or pharmacology (transporting bodies using principles of water pressure). Inspired by Conan, I found the essence of math: it is never used alone, and everything is based on math.

The solar cooking project proved my theory about math. After our group bought a vacuum tube and an electronic thermometer, one classmate suggested that the best time to use solar energy must be 12 p.m. But the Conan inside me reminded of the truth of solving problems: interdisciplinary methods. I suggested to measure the interior temperature of the tube, the atmosphere temperature, and the angle between the film and sunlight at different time periods. Then we used mathematical modeling to determine the relationship of those factors. I saw a straight line, where the scattered points on both sides were evenly distributed, forming through various transformations of coefficients. Thus, instead of subjectively deducting, we pinpointed the theoretically optimal time. Besides, when first learning linear algebra, I found no applied value of those matrices. However, one time I was using Google Map, I found I and the map were in two different dimensional worlds. That reminded me of linear mapping which projects one element in space A to space B. I guessed the programmers were actually projecting coordinates in the real 3D world into 2D map, vice versa. Such a perfect example of math and cartography.

There is always a Conan in me, desiring to figure out the truth of the world by combining math and other subjects.