Prep里的两道题，之前的讨论里没有。

(1) when t is divided by 7, the remaider is 6;

(2)when t^2 is divided by 7, the remaider is 1;

答案是A，不知道怎么做的。

2. What is the greatest possible area of a triangular region with one vertex at the center of a circle of radius 1 and the other two vertices on the circle?

我觉得应该是等边三角形，但是答案是1/2，请牛人指点。