高一数学已知３的a次方＝５的b次方＝m且(１／a)+(1/b)=
已知３的a次方＝５的b次方＝m 且(１／a)+(1/b)=2 求m的值
3^a = 5^b = m a = log(3)m， b = log(5)m 1/a = log(m)3， 1/b = log(m)5 （换底公式） 1/a + 1/a = log(m)3 + log(m)5 = log(m)15 = 2 所以 m^2 = 15 又 m > 0 所以 m = 根号15