question_answer

If \[\frac{d}{dx}\left( \frac{1+{{x}^{4}}+{{x}^{8}}}{1+{{x}^{2}}+{{x}^{4}}} \right)=a{{x}^{3}}+bx\], then

A) \[a=4,\text{ }b=2\]       

B)  \[a\text{ }=4,\text{ }b\text{ }=-2~\]

C) \[a\text{ }=\text{ }-2,\text{ }b\text{ }=\text{ }4~~\]

D)  \[a=\text{ }2,\text{ }b=4\]