[R] problem with abline and lines

[Martin Ivanov]

 Dear R users,

I need to plot to perpendicular straight lines. However, although I set the coefficients 
so that the lines are perpendicular, they do not look to be so in the plot. Here is a minimal working example:
plot(x=c(-1, 1), y=c(-1, 1)); abline(a=0, b=1/sqrt(2)); abline(a=0, b=-1/sqrt(2))

Please tell me if the same problem is valid by you. I am running R-2.10.1 on Linux.

Is there a way out of this?

Regards,

Martin