Plotting TF1 Function

Dear Root Folks,

I don't simply understand when I draw this function. Please see the short script I append below.

If you look at this funtion you can see the asmyptote at x=-48.43.

That means that the curve is going quickly either in the -infinity or +infinity as it approaches this value from x = +/-infinity.  

That means there shouldn't be a curve or a line that seems to cross this asymptote.

I just find this strange.

What is wrong with my code?

Version 4.04/02 6 June 2005
gcc version 3.4.2 20041017 (Red Hat 3.4.2-6.fc3)

Thanks

-- 
Zaldy A. Nawang


void tmp()
{
TF1 * fd = new   
TF1("fd",
"-(0.54*TMath::Sin(0.004*(x+48.43)))/((1-TMath::Cos(0.004*(x+48.43)))*(1-TMath::Cos(0.004*(x+48.43))))",
-58.43,-38.43);

	fd->SetNpx(10000);
	fd->SetLineWidth(1);
	fd->SetLineColor(2);
	fd->Draw();

	fd->Draw();
	gPad->Modified();
	gPad->Update();
}