任意函数的迈克劳林展开式为
据此可以求得:
arctanx(x)=x-1/3*x^3+1/5*x^5-1/7*x^7+1/9*x^9+...+(-1)^(n+1)/(2n-1)*x^(2n-1)
tan(x)=x+1/3*x^3+2/15*x^5+17/315*x^7+62/2835*x^9+...+[2^(2n)*(2^(2n)-1)*B(2n-1)*x^(2n-1)]/(2n)!
arctanx(x)前五项是:x-1/3*x^3+1/5*x^5-1/7*x^7+1/9*x^9;
第n项是 [(-1)^(n+1)*x^(2*n-1)]/(2*n-1);
拉格朗日余项是:
第n项是 (-1)^(n+1)*x^(2*n-1)/(2*n-1);
tan(x)前五项是:x+1/3*x^3+2/15*x^5+17/315*x^7+62/2835*x^9;
拉格朗日的余项只要把最后一项f(x)的n+1次方导数换成f(ξ)的n+1次方导数就行了,其它的不变
arctanx(x)=x-1/3*x^3+1/5*x^5-1/7*x^7+1/9*x^9
tan(x)=x+1/3*x^3+2/15*x^5+17/315*x^7+62/2835*x^9
arctanx(x)前五项是:x-1/3*x^3+1/5*x^5-1/7*x^7+1/9*x^9;
tan(x)前五项是:x+1/3*x^3+2/15*x^5+17/315*x^7+62/2835*x^9;
arctanx(x)=x-1/3*x^3+1/5*x^5-1/7*x^7+1/9*x^9
tan(x)=x+1/3*x^3+2/15*x^5+17/315*x^7+62/2835*x^9