如图
原式 = lime^(2-2cosx){e^[x^2-(2-2cosx)] - 1} / x^4= lim{e^[x^2-(2-2cosx)] - 1} / x^4= lim[x^2-(2-2cosx)]/x^4 = lim(2x-2sinx)/(4x^3)= lim(x-sinx)/(2x^3) = lim(1-cosx)/(6x^2)= lim(x^2/2)/(6x^2) = 1/12
