The author explores the solution to the best time problem according to three ways of thinking, including basic trigonometric identity, geometrical optics of physics and Geometer's Sketchpad.
Unfortunately, the solution still included a complicated set of sums of algebraic series involving tricky powers of trigonometric functions.
不幸的是，这一方法仍然包含了一系列复杂的代数计算，还涉及了复杂得三角函数。
3
According to the boundary conditions of the curved slab, an analytical solution by trigonometric series and an approximate solution by method of finite strips have been given.