Question

【ACM题】一道ACM题，我只要想知道在数学上如何求解。

我不会做这道题，所以打不出编程的程序。
不需要会写代码，只要告诉我数学上如何分析解决就行了。
请各位详细讲下这道题的解决办法，万分感谢！！

Turn the corner：

Mr. West bought a new car! So he is travelling around the city.
One day he comes to a vertical corner. The street he is currently in has a width x, the street he wants to turn to has a width y. The car has a length l and a width d.
Can Mr. West go across the corner?

Input

four real numbers, x, y, l and w.

Output

If he can go across the corner, print "yes". Print "no" otherwise.

Sample Input

10 6 13.5 4
10 6 14.5 4

Sample Output

yes
no

Answer 1

如上图，这个问题就是一个矩形的一边的2个点分别固定在x和y轴上，该边和x轴的夹角θ在0到π/2的范围内滑动，看另一边所代表的直线y = -tanθ*x+w/cosθ+l*sinθ在θ滑动的过程中会不会滑到点（x,y）的上方 即求f(θ) = w/cosθ+l*sinθ-tanθ*x-y的最大值是否大于0 我的求法是对f(θ)求导，得f'(θ),再用二分法求f'(θ)=0的点θ1，判断f(θ1)是否大于0 使用该思路成功AC......

Answer 2

求高人解答