We have indeterminateness of type
0/0,
i.e. limit for the numerator is
x→4π+lim(1−sin(2x))=0and limit for the denominator is
x→4π+lim(π−4x)=0Let's take derivatives of the numerator and denominator until we eliminate indeterninateness.
x→4π+lim(π−4x1−sin(2x))=
x→4π+lim(dxd(π−4x)dxd(1−sin(2x)))=
x→4π+lim(2cos(2x))=
x→4π+lim(2cos(2x))=
0It can be seen that we have applied Lopital's rule (we have taken derivatives with respect to the numerator and denominator) 1 time(s)