Question

第七题数学过程

Answer 1

f(x)=Asin(2x+π/6)，正确。

f(2π/3)=Asin(4π/3+π/6)=Asin(3π/2)=-A；

2π/3=6.28/3=2.09≈2.

故f(2)≈f(2π/3)=-A;【 即f(2)最小】

f(-2)≈f(-2π/3)=Asin(-4π/3+π/6)=Asin(-7π/6)=-Asin(7π/6)=-Asin(π+π/6)

=Asin(π/6)=A/2; 【∵-2>-2.09=-2π/3,故 f(-2)略小于f(0)】 

f(0)=Asin(π/6)=A/2.

即应该有f(2)<f(-2)<f(0)，应选A.