# logic change signs

irr_f3<-function(cashflows,bigV=100000){

   smallV<-1e-5
   a<--1+smallV
   rates<-seq(a,1,smallV)
   sign1<-sign(npv_f(a,cashflows))

   for(r in rates){
        npv<-npv_f(r,cashflows)
        sign2<-sign(npv)
        #print(r)
        if(sign1+sign2==0){
             cat("irr =",r,"\n")
             sign1<-sign2
        }
   }
}


cashflows<-c(-17,16,16,16,16,-52)*1000
irr_f3(cashflows)