Friedrich Miescher discovered DNA in 1869, isolating "nuclein" from pus cell nuclei.
Key points:
Therefore, Friedrich Miescher is credited with the initial discovery of DNA.
Given, the function \( f(x) = \frac{a^x + a^{-x}}{2} \) (\( a > 2 \)), then \( f(x+y) + f(x-y) \) is equal to