The value of {cos ^2},{10^o},, - ,cos ,,{10^o | vedclass

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Question

$\frac{1}{2}\,(2\,{\cos ^2}{10^o}\, - \,2\cos \,{10^o}\,\cos \,{50^o} + \,2\,{\cos ^2}{50^o})$

$ \Rightarrow \frac{1}{2}\,(1 + \,\cos \,{20^o} - (\

Vedclass · Accepted Answer

$\frac {3}{4}$

Vedclass · Answer

$\frac{1}{2}\,(2\,{\cos ^2}{10^o}\, - \,2\cos \,{10^o}\,\cos \,{50^o} + \,2\,{\cos ^2}{50^o})$

$ \Rightarrow \frac{1}{2}\,(1 + \,\cos \,{20^o} - (\cos \,{60^o} + \cos \,{40^o})\, + 1 + \,\,\cos {100^o})$

$ \Rightarrow \frac{1}{2}\,\left( {\frac{3}{2} + \,\cos \,{{20}^o} + 2\sin \,{{70}^o}\sin \,( - {{30}^o})} \right)$

$ \Rightarrow \frac{1}{2}\,\left( {\frac{3}{2} + \,\cos \,{{20}^o} - \sin \,{{70}^o}} \right)$

$ \Rightarrow \frac{3}{4}$

The value of ${\cos ^2}\,{10^o}\,\, - \,\cos \,\,{10^o}\,\cos \,\,{50^o}\, + \,{\cos ^2}\,{50^o}$ is

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