（1）∵幂函数y=f(x)图象过点(2,√2),∴设y=f(x)=x^a,∴√2=2^a∴a=1/2∴y=f(x)=x^1/2,∴f(9)=9^1/2=3(2)∵x^(2/3)＞x^(3/5)∴（x^(2/3)）^15＞(x^(3/5))^15∴x^10＞x^9∴x^9(x-1)＞0∴x∈（－∞,0）∪（1,＋∞）...