Lim (x-->0)((tanx-sinx)/x^3)
=lim(x-->0)(sec²x-cosx)/(3x²) (罗比达法则)
=lim(x-->0)(2secx*secxtanx+sinx)/(6x) (罗比达法则)
=lim(x-->0)(2sec³x*sinx+sinx)/(6x)
=lim(x-->0)(2sec³x+1)/6*(sinx/x)
=1/2
Lim (x-->0)((tanx-sinx)/x^3)
=lim(x-->0)(sec²x-cosx)/(3x²) (罗比达法则)
=lim(x-->0)(2secx*secxtanx+sinx)/(6x) (罗比达法则)
=lim(x-->0)(2sec³x*sinx+sinx)/(6x)
=lim(x-->0)(2sec³x+1)/6*(sinx/x)
=1/2