若圆内任意弦AB、弦CD交于点P,则PA·PB=PC·PD(相交弦定理) sinB=L/R B=asin(L/R) 反三角函数。 1#include<cstdio>2#include<cmath>3intmain()4{5intt;6scanf("%d",&t);7intnum=0;8while(t--)9{10doublel,n,c,L,le,ri,r,mid;11scanf("%lf %lf %lf",&l,&n,&c);12L=(1+n...