In[]:=
s=NDSolve[{y'[t]-{1,0}*y[t],y[0]{1,1}},y,{t,0,1}]
NDSolve
:Encountered non-numerical value for a derivative at t == 0..
Out[]=
NDSolve[{
′
y
[t]{-y[t],0},y[0]{1,1}},y,{t,0,1}]
In[]:=
s=NDSolve[{y'[t]-DiagonalMatrix[{1,0}].y[t],y[0]{1,1}},y,{t,0,1}]
Out[]=
yInterpolatingFunction
Domain: {{0.,1.}}
Output dimensions: {2}

In[]:=
Plot[y[t]/.s,{t,0,1}]
Out[]=