[R] numerical values in expressions

[Stephan Lorenzen]

Hi there, 

I fitted a curve to some data and want to write the equation of the
fitted curve in the figure legend. If I write 

paste(format(fitZ$estimate[1], digits=2), "e^", format(fitZ$estimate[2],
digits=2), "x +", format(fitZ$estimate[3], digits=2))

i get unformatted output, writing "e^-0.0039x" instead of superposing
the exponent. I tried several variants of "expression", but finally only
the explicit one 

expression(0.061 * e^"-0.0039x" + 0.010)

where I have to provide the values myself worked. Is there any way to
use the "expression" function to reference actual values of variables
instead of just outputting their names?

Thanks,

Stephan