1 =lim[cos((x+4)/2)sin((x-4)/2]/(x-4)=limcos((x+4)/2)[sin((x-4)/2]/[(x-4)/2]=limcos((x+4)/2)lim[sin((x-4)/2]/[(x-4)/2]=limcos((x+4)/2)=cos42.分子分母除以x^50=lim(2-1/x)^30(3-2/x)^20/(1+1/x)^50=2^30(3)...
1 =lim[cos((x+4)/2)sin((x-4)/2]/(x-4)=limcos((x+4)/2)[sin((x-4)/2]/[(x-4)/2]=limcos((x+4)/2)lim[sin((x-4)/2]/[(x-4)/2]=limcos((x+4)/2)=cos42.分子分母除以x^50=lim(2-1/x)^30(3-2/x)^20/(1+1/x)^50=2^30(3)...