已知3^a=4^b=36,求2/a + 1/b
问题描述:
已知3^a=4^b=36,求2/a + 1/b
答
3^a=4^b=36,则:
a=log(3)36,b=log(4)36,则:
1/a=log(36)3,1/b=log(36)4
所以,2/a+1/b=2log(36)3+log(36)4=log(36)9+log(36)4=log(36)[9×4]=1