Hi,

Please help,

Do you know of any package or mathematical library for handling alphanumeric variables?

I explain what I try to do is multiply matrix numeric with matrix no numeric.

Example (done with the software TI-Nspire):

The code in R is:

```
y <- c( 26.5, 28.1, 25.2, 26.0, 24.0)
xmain <- c(0.040, 0.041, 0.055, 0.056, 0.062)
x1 <- rep(1,length(xmain))
b <- c("b0","b1")
mx<- cbind(x1,xmain)
ei <- y - (mx %*% b)
```

The error message is:

*Error in mx %*% b : requires numeric/complex matrix/vector arguments*

I hope you can help me,

thanks