Question

lim x→π sin3x/tan5x 怎么算

Answer 1

let
y=x-π

lim(x->π) sin3x/tan5x
=lim(y->0) sin[3(π+y)]/tan[5(π+y)]
=lim(y->0) sin(3π+3y)/tan(5π+5y)
=lim(y->0) -sin(3y)/tan(5y)
=-lim(y->0) (3y)/(5y)
=-3/5

Answer 2

=-lim sin(3π-3x)/tan(5π-5x)
=-lim (3π-3x)/(5π-5x)
=-3/5