rates<-seq(0,1,2e-2)
cashflows<-c(-17,16,16,16,16,-52)*1000
npvs<-npv_f(rates,cashflows)
#
title<-"Multiple IRR illustration"
x<-"Discount Rate"
plot(rates,npvs,main=title,xlab=x,ylab="NPV",type='b',lwd=3)
# add a line
x1<-rates
y1<-x1*0
lines(x1,y1,lwd=1)