ClearAll[Evaluate[Context[]<>"*"]]

SetDirectory[NotebookDirectory[]]

ClearAll

FileNames["*.xls"]

pom1=Import["koeficientyReal.xls"];
Length[pom1];
pom2=pom1[[1]];
info=pom2[[1]];
pom3=DeleteCases[pom2,info];
MatrixForm[pom3];
praveStrany1=pom3\[Transpose][[-1]];
praveStrany2=Last/@pom3;
matice1=DeleteCases[pom3\[Transpose],praveStrany1]\[Transpose];
matice2=Take[#,10]&/@pom3;
matice3=Drop[#,-1]&/@pom3;
reseni1=LinearSolve[matice1,praveStrany1];
reseni2=Inverse[matice1].praveStrany1;
%-%%//Chop;
promenne=(Subscript[x, #])&/@Range[Length[praveStrany1]];
Table[(Subscript[x, i]),{i,1,Length[praveStrany1]}];
rovnice=Thread[matice1.promenne==praveStrany1];
sol=Solve[rovnice][[1]];
reseni2-promenne/.sol//Chop;

ClearAll[Evaluate[Context[]<>"*"]]
pom1=Import["koeficientyKomplex.xls"];
pom2=pom1[[1]];
info=Take[pom2,2];
pom3=Drop[pom2,{1,2}];
pom4=(Partition[#,2]&/@pom3)/.{re_Real,im_}:>re+I*im;
pom5=Table[pom3[[i,j]]+I*pom3[[i,j+1]],{i,Length[pom3]},{j,1,Length[pom3[[1]]]-1,2}];
(pom5-pom4)/.List->Plus;
praveStrany1=pom5\[Transpose][[-1]];
matice1=DeleteCases[pom5\[Transpose],praveStrany1]\[Transpose];
reseni1=LinearSolve[matice1,praveStrany1];

rce=5y''[t]+11y'[t]+2y[t]==((Sin[t])/(t+1));
DSolve[rce,y[t],t]

rce=5y''[t]+11y'[t]+2y[t]==((Sin[t])/(t+1));
DSolve[rce,y[t],t]

DSolve[{rce,y[0]==1,y'[0]==5},y[t],t];

DSolve[{rce,y[0]==1,y[1]==5},y[t],t];