lim h趋向0 (x+h)^2-x^2/h

lim h趋向0 (x+h)^2-x^2/h 如何证明lim[f(x+h)+f(x-h)-2f(x)]=f(x) 其中h趋向0 f(x)在x处二阶可导,求lim{[f(x+h)-2f(x)+f(x-h)]/h^2},h趋向于0 f(x+y)=f(x)+f(y)+2xy lim f(h)/h =0 h 趋向0 问f'（x) 和f(x) lim[√（h＋x）－√x]/h h趋向于0 lim(h趋向于0）［sin(x+h)-sinx］／h lim h趋向于0 (x+h)的平方-x的平方/h 求极限,请写出过程 求lim【h→0】1/h∫【x-h→x+h】cost^2dt(h>0) lim h趋向0 (x+h)^3—x^3/h (即分母是h,分子是(x+h)^3) 求极限 请写下过程, lim[(x+h)^2-x^2]/h极限,h趋于0 lim(h→0) [a^(x+h)+a^(x-h)-2a^x]/h^2有谁帮个忙谢谢 1.lim x→0 3x/(sinx-x)2.lim x→0 (1-cosmx)/x^23.lim x→0 sin4x/[(√x+2)-√2]4.lim h →0 [sin(x+h)-sin(x-h)]/h 若f'(x)=-3,则lim (h趋向0)时f(x+h)-f(x-3h)/h=?急!步骤! f(x)在x=a处可导, lim(h→0) [f(a+h)-f(a-2h)]/h= lim(h→0)[(x+h)^3-x^3]/h f'(x)=2.则lim[f(x-h)-f(x+2h)]/2h lim(x趋向0) x^2 / (sin^2) * x/3 lim(x趋向0) x^2 / (sin^2) * x/3