2.
对于平面直角坐标系中的任意两点\(P_{1}(x_{1},y_{1})\),\(P_{2}(x_{2},y_{2})\),我们把:\(d(P\)\({\,\!}_{1}\),\(P\)\({\,\!}_{2}\)\()=|x\)\({\,\!}_{1}\)\(-x\)\({\,\!}_{2}\)\(|+|y\)\({\,\!}_{2}\)\(-y\)\({\,\!}_{2}\)\(|\)叫做\(P\)\({\,\!}_{1}\)、\(P\)\({\,\!}_{2}\)两点间的直角距离.
\((1)\) 若点\(A(1,1)\),点\(B(3,4)\),则\(d(A,B)=\)_______;
\((2)\)若点\(E(a,a)\),点\(F(2,2)\),且\(d(E,F)=4\),求\(a\)的值;
\((3)\)若点\(M(m,2)\),点\(N(1,0)\),求\(d(M,N)\)的最小值。