# Thread: Prove the following equality

1. ## Prove the following equality

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any idea that help in proving this equality is appretiated.

Thanks

2. Substitute the MacLaurin series for $\displaystyle e^z, e^{-\frac{1}{2}z}$ and $\displaystyle \cos{\frac{z\sqrt{3}}{2}}$ into RHS and simplify...