r语言拟合报错Error in lhs - rhs : non-numeric argument to binary operator

Question

想进行回归拟合。报错

csj=read.xlsx('C:/Users/86182/Desktop/11.xlsx',detectDates = TRUE,fillMergedCells = TRUE)
Scurve=function(X,a,b)
  return(a*(e^b)*X)
csj[,c(1:2)]<-as.numeric(unlist(csj[,c(1:2)]))
  fit<-nls(formula = Y~Scurve(X,a,b),
         data=csj,
         start=list(a=10,b=12))

cc

改变类型也不行

想拟合模型系数