e^x= 1+x+x^2/2!+x^3/3!+...+x^n/n!+Rn(x）
ln(1+x)= x-x^2/2+x^3/3-...(-1)^(k-1)*x^k/k+Rn(x)(|x|<1)
sin x = x-x^3/3!+x^5/5!-...(-1)^(k-1)*x^(2k-1)/(2k-1)!+Rn(x)(-∞<x<∞)
cos x = 1-x^2/2!+x^4/4!-...(-1)^k*x^(2k)/(2k)!+... (-∞<x<∞)
arcsin x = x + 1/2*x^3/3 + 1*3/(2*4)*x^5/5 + ... (|x|<1)
arccos x = π - ( x + 1/2*x^3/3 + 1*3/(2*4)*x^5/5 + ... ) (|x|<1)
arctan x = x - x^3/3 + x^5/5 - ... (x≤1)
sinh x = x+x^3/3!+x^5/5!+...(-1)k-1*x^(2k-1)/(2k-1)!+... (-∞<x<∞)
cosh x = 1+x^2/2!+x^4/4!+...(-1)k*x^(2k)/(2k)!+... (-∞<x<∞)
arcsinh x = x - 1/2*x^3/3 + 1*3/(2*4)*x^5/5 - ... (|x|<1)
arctanh x = x + x^3/3 + x^5/5 + ... (|x|<1)