Find value of $\sum\limits_{k=0}^{10}{(-1)^k C(10,k)/(2^k)}$ 
Find value of $\sum\limits_{k=0}^{10}{(-1)^k\dbinom{10}{k}\dfrac{1}{2^k}}$

Do I have to open the factorials of all combinations, or is there any other way? please help.

HINT
$$\sum_{k=0}^{10}\left(\frac{-1}{2}\right)^k\cdot \binom{10}{k}\cdot1=\left(1-\frac{1}{2}\right)^{10}$$
