cos (z) can be expressed as – McqOptions

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1.	cos (z) can be expressed as
A.	\(\frac{1}{2}\left( {{e}^{i~z}}+{{e}^{-i~z}} \right)\)
B.	\(\frac{1}{2}\left( {{e}^{i~z}}-{{e}^{-iz}} \right)\)
C.	\(\frac{1}{2i}\left( {{e}^{i~z}}+{{e}^{-iz}} \right)\)
D.	\(\frac{1}{2i}\left( {{e}^{i~z}}-{{e}^{-iz}} \right)\)
Answer» B. \(\frac{1}{2}\left( {{e}^{i~z}}-{{e}^{-iz}} \right)\)

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