Optimal Choice

Life is structured by a rational behavior or what we can say the altruism and the self-interest behavior make our all interaction. All people live on "indifferent curve" and also to be work hard to maintain "marginal rate of substituation" that means keeping the quality of life.

Sometimes, we use the completeness theorem to find out what we love, but sometimes we like the monotonicity theorem to own the more and the better.

Whether choosing goods or bads, we come toward our preference, even though protruding(convex?) or concave to the origin that means "do nothing" which can make we feel happy and better not to be angry or other bad moods more.

Where can we find the "Optimal Choice"？I think it doesn't only exist in the class and also to be everywhere especially in our life.

「千金難買早知道。」萬般無奈想不到╮(╯_╰)╭








上文已經夠屬於小學生的英文作文了，結果...竟想不到那個「千金難買」的英文片語，所以才打中文的啦....囧rz