lim(x→∞)(3x^2+1)/(5x+1)sin(2/x)怎么做?求详解
=lim(x→∞)[(3x^2+1)/(5x+1)] (2/x) sin(2/x)→2/x 当x→∞
=lim(x→∞)[(3x^2+1)*2]/(5x+1)*x
=lim(x→∞)[6x²+2]/[5x²+x]
=6/5=1.2