求极限!分母为零!像lim h→0 ((1+h)^(1/2)-1)/h和lim x→-1 (x^2+2x+1)/(x^4

求极限!分母为零!像lim h→0 ((1+h)^(1/2)-1)/h和lim x→-1 (x^2+2x+1)/(x^4 求解一道高数极限题lim[tan(x+h)-2tanx+tan(x-h)]/h² h→0 答案为2sec
求极限,分母为零.lim x to -1 (x^2-4x)/(x^2-3x-4)lim x to 1 (x^3-1)/( 设f'(x) = 3^(1/2) ,求 lim(h→0) [f(x+mh) - f(x - nh)] / h ,(m , 导数极限形式的证明1）f'(x0)=lim(x→x0)[f(x)-f(x0)]/(x-x0) 2)f'(x)=lim(h 已知lim（x→1）g（x）=lim（x→1）h(x)=2,且g（x）≤f（x）≤h（x）,则lim（x→1）[2x^2 设f(x)在x=2处可导,且f'(2)=1,则lim h→0 [ f(2+h)-f(2-h)]/h等于多少, 求lim(x→0)x cos 1/x lim(x→∞)x^2/ (3x-1)的极限 极限lim(x→0)(1-2/x)^x 求极限lim x→π(sin3x)/(x-π)和求极限lim x→π/2(1+cosx)secx 求极限lim(x-->0)x^2 sin(1/x), 1.4求极限lim(x→∞) (x^2+x)/ (x^4-3x^+1)