I'll show you number 1.
Define the function $\displaystyle g(a)=f(a)-f(a+1/2)$ and note it is continuous. Then, we have $\displaystyle g(0) = f(0)-f(1/2)$ and $\displaystyle g(1/2) = f(1/2)-f(1)$. Depending on the size of f(1/2) relative to f(0)=f(1), we either have g(a) goes from negative to positive or positive to negative. In either case, we have that g(a) = 0 at some point from 0 to 1/2. This shows number 1.