[求助]两道数学题！

lingdang1988

1. In the figure 1, points P and Q lie on the circle with center O. What is the vaule of S? Answer: 1

图形中，圆的中心就是坐标原点，左边与圆相交的点的坐标是 P（－根号3, 1）, 右边的点是Q (s, t)

ATH connecttype="rect" gradientshapeok="t" extrusionok="f">ATH>ATH connecttype="none" extrusionok="t">ATH>INE>INE>INE>INE>INE>INE>INE>INE>INE>INE>2. Before being simplified, the instructions for computing income tax in country R were to add 2 percent of one's annual income to the average (arithmetic mean) of 100 units of country R's currency and 1 percent of one's annual income. Which of follwing represents the simplified formula for computing the income tax, in country R's currency, for a person in the country whose annual income is M? Answer:50+M/40

解不出来，麻烦大家帮忙看看了！第二题，我都读不懂是什么意思！唉！谢谢了！

monicars

1.因为是同一个圆，OP=OQ. 于是可以得出s^+t^=4

2.两点距离，PQ^＝2^+2^＝（－根号3－s)^+(1-t)^=3+2根号3＋s^+1-2t+t^=8,综合1，可以推出t=根号3s.再带回1，得出s^=1

himba

1.OP的斜率为(1-0)/(-V3-0)=-1/V3

OQ与OP垂直，所以斜率积＝-1，（t-0)/(s-0)*(-1/V3)=-1

t=s/V3---->(1)

因半径＝V[(1-0)^2+(V3-0)^2]=2

V(t^2+s^2)=2---->(2)

(1)(2)联立得s=1

2. Before being simplified, the instructions for computing income tax in country R were to add 2 percent of one's annual income to the average (arithmetic mean) of 100 units of country R's currency and 1 percent of one's annual income. Which of follwing represents the simplified formula for computing the income tax, in country R's currency, for a person in the country whose annual income is M? Answer:50+M/40

在简化前，计算R国收入所得税得方法是：一个人收入的2％+100该国货币和该人收入1％的平均数。

所以，2%M+(100+1%M)/2=50+M/40