# cos 360 + cos 234 + cos 162 + cos 18 = ? Note - numbers are in degree.

Question
$$\displaystyle{\cos{{360}}}+{\cos{{234}}}+{\cos{{162}}}+{\cos{{18}}}=$$ ?
Note - numbers are in degree.

2021-02-26
$$\displaystyle{\cos{{\left({18}\right)}}}={0.9510565162951535}$$
$$\displaystyle{\cos{{\left({162}\right)}}}=-{0.9510565162951535}$$...add this much & yu get zero
$$\displaystyle{\cos{{\left({360}\right)}}}={k}{o}{\sin{{e}}}{\left({0}\right)}={1}$$
$$\displaystyle{\cos{{\left({234}\right)}}}=-{0.5877852522924732}$$

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