y=a^x x1=m,x2=n a^m+a^(-m)-[a^n+a^(-n)] =y1+1/y1-y2-1/y2 =(y1^2+1)/y1-(y2^2+1)/y2 =(y1-y2)(y1y2-1)/(y1y2) 1.a>1 y=a^x 为增函数 因为m>n>0 所以,a^m>a^n,即y1>y2 y1y2=a^(m+n)>a^0=1 所以(y1-y2)(y1y2-1)/(y1...