Question

若a+b=2.那么5^a+5^b的最小值是?

Answer 1

5^a+5^b

≥2√(5^a*5^b)

=2√[5^(a+b)]

=2√25

=10

当且仅当5^a=5^b,即 a=b=1时等号成立

∴ 5^a+5^b的最小值是10