已知（sinx）^2+3a^2cosx-2a^2(3a-2)-1=0有实根，求a的范围

热心网友

(sinx)^2+3a^2*cosx-2a^2*(3a+2)-1=0---(cosx)^2-3a^2*cosx+2a^2(3a+2)=0---(cosx+2a)[cosx-(3a^2+2a)]=0---cosx=-2a, or 3a^2+2a|cosx|=-1/2=3a^2+2a+1=(3a-1)(a+1)= a∈Φ or -1=-1=