Question

x+2y=1,求2^x+4^y的最小值?

Answer 1

因为x+2y=1则x=1-2y;

2^x+4^y=2^(1-2y)+2^(2y)

=2/(2^(2y))+2^(2y)

>=2根号下(2/(2^(2y))*2^(2y))

=2根号下2