分类：教育/科学-学习帮助
问题：求下列极限:(1)limx/tan3x(x趋向于0)(2)lim 
(1) lim  x/tan 3x   (x趋向于0)(2) lim  sin3x/sin5x     (x趋向于0)(3) lim  (sinx*tanx)/x^2      (x趋向于0)(4) lim  (1-c2x)/xsinx       (x趋向于0)
回答：(1) lim x/tan 3x (x趋向于0)=1/3*lim 3x/tan 3x (x趋向于0)=1/3

(2) lim sin3x/sin5x (x趋向于0)3/5*lim (sin3x/3x)/(sin5x/5x) 
(x趋向于0)=3/5
(3) lim (sinx*tanx)/x^2 (x趋向于0)=
lim (sinx)/x (x趋向于0)*lim (tanx)/x (x趋向于0)=1*1=1
(4) lim (1-cos2x)/xsinx (x趋向于0)=lim(2sinx平方)/( xsinx)
=2