Question

判断函数y=(x-5)(2-x)的单调性.职高的数学题,

Answer 1

y=(x-5)(2-x)

=-(x-5)(x-2)

对称轴：x=-b/(2a)=(5+2)/2=7/2

当x＜7/2时,单调递增

当x≥7/2时,单调递减