y=log2[(3-sinx)/(3+cosx)]的值域

问题描述:

y=log2[(3-sinx)/(3+cosx)]的值域

t=(3-sinx)/(3+cosx)3t+tcosx=3-sinxsinx+tcosx=3-3y√(t²+1)sin(x+w)=3-3ysin(x+w)=(3-3y)/√(y²+1)因|sin(x+w)≤1,则:|(3-3t)/√(t²+1)|≤1|3-3t|≤√(t²+1)(3-3t)²≤t²+18t²...