We have indeterminateness of type
0/0,
i.e. limit for the numerator is
x→0+limsin4(x)=0and limit for the denominator is
x→0+limx4=0Let's take derivatives of the numerator and denominator until we eliminate indeterninateness.
x→0+lim(x4sin4(x))=
Let's transform the function under the limit a few
x→0+lim(x4sin4(x))=
x→0+lim(dxdx4dxdsin4(x))=
x→0+lim(x3sin3(x)cos(x))=
x→0+lim(x3sin3(x))=
x→0+lim(dxd4x3dxd4sin3(x))=
x→0+lim(x2sin2(x)cos(x))=
x→0+lim(x2sin2(x))=
x→0+lim(dxd12x2dxd12sin2(x))=
x→0+lim(xsin(x)cos(x))=
x→0+lim(xsin(x))=
x→0+lim(dxd24xdxd24sin(x))=
x→0+limcos(x)=
x→0+lim1=
x→0+lim1=
1It can be seen that we have applied Lopital's rule (we have taken derivatives with respect to the numerator and denominator) 4 time(s)