文档介绍：已知方程x2+ax-b=0的根是a和c,方程x2+cx+d=,a、b、c、d为不同实数,求a、b、c、、(本大题满分25分)如图,四边形A1A2A3A4内接于一圆,△A1A2A3的内心是I1,△A2A3A4的内心是I2,△:(1)A2、I1、I2、A3四点共圆;(2)∠I1I2I3=、(本大题满分25分)如图,将3枚相同硬币依次放入一个4×4的正方形格子中(每个正方形格子只能放1枚硬币).求所放的3枚硬币中,任意两个都不同行且不同列的概率.∴∠I1I2A3=180o-∠I1A2A3=180o-21∠A1A2A3同理∠I3I2A3=180o-∠I3A4A3=180o-21∠A1A4A3············································20分∴∠I1I2I3=360o-(∠I1I2A3+∠I3I2A3)=21(∠A1A2A3+∠A1A4A3)=90o···················25分五、(本大题25分)解:1、计算总的放法数N:第一枚硬币放入16个格子有16种放法;第二枚硬币放入剩下的15个格子有15种放法;,总的放法数N=16×15×14=3360.·············································10分2、计算满足题目要求的放法数m:第一枚硬币放入16个格子有16种放法,,,,满足题目要求的放法数m=16×9×4=576.···································20分所求概率P=3561415164916??????Nm.···················································25分