Error Bands around TF1

[wellatiger]

Dear Rooters,

I have TF1 TF1 *f = new TF1("f","x/TMath::Sqrt((x*x) + (0.938*0.938))",0, 2) and I want to draw 1 Sigma error band around it, can you help me?

Thank you in advance

[Wile_E_Coyote]

Functions have no errors.