高數函數求極限 1.lim(x→0)(x^3-2x^2+3X)/(2x^4+x^3+x) 2.lim(x→0)(1-3x)^1/x -1 3.lim(x→0)[(√1+sinx)-(√1-sinx)]/x 4.lim(x→0)[ln(1-2x)]/x (鬱悶,做了半天一對答案全不對,老傷心了!)

高數函數求極限 1.lim(x→0)(x^3-2x^2+3X)/(2x^4+x^3+x) 2.lim(x→0)(1-3x)^1/x -1 3.lim(x→0)[(√1+sinx)-(√1-sinx)]/x 4.lim(x→0)[ln(1-2x)]/x (鬱悶,做了半天一對答案全不對,老傷心了!)

1.原式=lim(x→0)(x²;-2x+3)/(2x³;+x²;+1)=3/1=3
2.原式=lim(x→0)[(1-3x)^(1/(-3x))]^[3(x-1)]
=e^{lim(x→0)[3(x-1)}
=e^(-3)=1/e³;
3.原式=lim(x→0){[√(1+sinx)-√(1-sinx)]/x}
=lim(x→0){2(sinx/x)/[√(1+sinx)+√(1-sinx)]}
=2[lim(x→0)(sinx/x)]/{lim(x→0)[√(1+sinx)+√(1-sinx)]}
=2*1/2
=1
4.原式=ln{lim(x→0)[(1-2x)^(1/x)]}
=ln{lim(x→0)[(1-2x)^(1/(-2x))]}^(-2)
=ln[e^(-2)]
=-2