question_answer

Which among the following is different?

\[\mathbf{2}\,\mathbf{co}{{\mathbf{s}}^{\mathbf{2}}}\mathbf{30{}^\circ  }-\mathbf{ 1,}\]\[\mathbf{1 }-\mathbf{ 2 si}{{\mathbf{n}}^{\mathbf{2}}}\mathbf{30{}^\circ }\]

\[\mathbf{co}{{\mathbf{s}}^{\mathbf{2}}}\mathbf{30{}^\circ  }-\mathbf{ si}{{\mathbf{n}}^{\mathbf{2}}}\mathbf{30{}^\circ , }\frac{\mathbf{1}-\mathbf{ta}{{\mathbf{n}}^{\mathbf{2}}}\mathbf{ 30{}^\circ }}{\mathbf{1+ta}{{\mathbf{n}}^{\mathbf{2}}}\mathbf{30{}^\circ }}\]

A)  \[2\text{ }co{{s}^{2}}30{}^\circ -1~\]                                               

B)  \[1\text{ }-\text{ }2 si{{n}^{2}}30{}^\circ \]

C)  \[co{{s}^{2}}30{}^\circ -si{{n}^{2}}30{}^\circ \]                            

D)  \[\frac{1-{{\tan }^{2}}\text{ 30}{}^\circ }{1+{{\tan }^{2}}\text{ 30}{}^\circ }\]

E)  None of these