三角函数公式证明发布会
Have you ever imagined that the starry sky above is a navigation guide written over millennia?
As Sheldon explained to Penny, the prologue of science often begins with a look upward. On a misty midsummer night over two thousand years ago, when an ancient sage gazed up, he saw perhaps not only the Milky Way, but the vast puzzle of space and order.
Yet in the East, more than a thousand years ago, the astrologers of Dunhuang had already channeled this awe into precise star charts. These were not just artistic treasures, but among humanity’s earliest attempts to quantify the heavens and mark our own place within them. But true history holds more weight than drama. These charts, born from an ancient ambition to measure the cosmos, drifted overseas in modern times, falling silent behind a display case at the British Library—a suspended memory of civilization.
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From Sheldon’s whiteboard, to Li Chunfeng’s star charts, to Rain’s photograph—this thread helps us understand: Trigonometry was never dry formulas. It is the coordinate sought in Zhang Dai’s The Night Ferry, the survival wisdom our ancestors used to navigate their vessels through stormy seas. And today, by retracing this path of proof, we are here to experience for ourselves that eternal romance—of turning curiosity into inquiry, inquiry into knowledge, and knowledge into legacy.
Trigonometric formulas are numerous—double-angle, half-angle, reduction, sum-to-product… Learning them often feels like an ordeal. But in today’s math class, formulas are no longer lines to be memorized; students have turned into the “launchers,” “explainers,” and “creators” of formulas.
In the math exhibition area, there was no rote recitation, only the light in their eyes and the fire of logic. The presenters, like true explorers, explained the ins and outs of each step with passion; the “audience”—classmates and teachers—listened intently, sometimes questioning, sometimes engaging in lively discussions with the presenters.
The children’s posters were meticulous, with rigorously logical derivations, already showing a professional touch. But even more delightful were the ingenious ideas they sparked to make abstract concepts “tangible”:
The team of Sammy and Simon used movable magnetic tiles to visually demonstrate that the blank area remains unchanged after moving triangles, ingeniously proving the angle sum formula. They operated and derived simultaneously, making each geometric relationship clear. This was not just wisdom, but the engineering spirit of turning thought into reality.
Two other groups, independently chose to start from the perspective of vectors, using more modern mathematical language to elegantly reconstruct the proof of the sum and difference formulas, demonstrating the interconnectedness of knowledge and the beauty of multiple solutions.
Excellent Posters
Their thinking has made mathematics, this once daunting classic discipline, once again burst with vitality and rekindle the passion for exploration in today’s classroom.