question_answer

\[Si{{n}^{\mathbf{4}}}\theta \text{ }+\text{ }Co{{s}^{\mathbf{4}}}\theta \]equals to__________

A)  \[1+2\text{ }si{{n}^{2}}\theta \text{ }co{{s}^{2}}\theta \text{        }\]                                    

B)  \[2\text{ }si{{n}^{2}}\theta \text{ }co{{s}^{2}}\theta \text{ }-\text{ }1\]

C)  \[1-2\text{ si}{{\text{n}}^{\text{2}}}\theta \text{ co}{{\text{s}}^{\text{2}}}\theta \]    

D)  \[3+2si{{n}^{2}}\theta \text{ }co{{s}^{2}}\theta \]

E)  None of these