2(b²/a+c²/b+a²/c)=(b^2/a+a^2/c)+(c^2/b+b²/a)+(a^2/c+c^2/b)>=2
√(b^2/a)*(a^2/c)+2√(c^2/b)*(b²/a)+2√(a^2/c)*(c^2/b)=2(b√a/c+c√b/a+a√c/b),即b²/a+c²/b+a²/c≥c√b/a+a√c/b+b√a/c.
2(b²/a+c²/b+a²/c)=(b^2/a+a^2/c)+(c^2/b+b²/a)+(a^2/c+c^2/b)>=2
√(b^2/a)*(a^2/c)+2√(c^2/b)*(b²/a)+2√(a^2/c)*(c^2/b)=2(b√a/c+c√b/a+a√c/b),即b²/a+c²/b+a²/c≥c√b/a+a√c/b+b√a/c.