2.
\((1)\)已知函数\(f(x)=1+\dfrac{a}{{{2}^{x}}+1}(a\in R)\)为奇函数,则\(a=\)____.
\((2)\)如图,若\(n=4\)时,则输出的结果为_______.
\((3)\)从圆\(\dfrac{1}{2}\)内任取一点\(P\),则\(P\)到直线\(x+y=1 \)的距离小于\(\dfrac{\sqrt{2}}{2}\)的概率____.
\((4)\)在\(\Delta ABC\)中,角\(A,B,C\)的对边分别是\(a,b,c\),若\( \dfrac{c}{\sin B}+ \dfrac{b}{\sin C}=2a \),\(b= \sqrt{2} \),则\(\Delta ABC\)面积是_______.