Suppose that a sequence x1,x2,…,x2001 of positive real numbers satisfies 3xn+12=7xnxn+1−3xn+1−2xn2+xn and x37=x2001. Find the maximum possible value of x1 .
In an acute-angled triangle ABC , a,b,c are sides, ma,mb,mc the corresponding medians, R the circumradius and r the inradius. Prove the inequality a+ba2+b2⋅b+cb2+c2⋅a+ca2+c2≥16R2rama⋅bmb⋅cmc.