已知函数f(x)=2根号3sinxcosx-2sin^2x+a,若f(x)有零点,求实数a的取值范围_数学解答

已知函数f(x)=2根号3sinxcosx-2sin^2x+a,若f(x)有零点,求实数a的取值范围

人气：481 ℃　时间：2019-09-20 05:41:54

解答

f(x)=√3sin2x+cos2x-1+a
=2sin(2x+π/6)-1+a=0有解
2sin(2x+π/6)=1-a
-2<=2sin(2x+π/6)<=2
所以-2<=1-a<=2
-1<=a<=3