l<-c(10000000,9795800,9782674,9770739,9759796,9749646,9740091,9731033,9722372,9713914,9705657,9697407,9689164,9680831,9672409,9663801,9655007,9646028,9636864,9627516,9617888,9607982,9597798,9587240,9576311,9565011,
     9553342,9541209,9528519,9515274,9501382,9486845,9471571,9455469,9438544,9420611,9401676,9381556,9360166,9337421,9313144,9287253,9259577,9229946,9198195,9164070,9127414,9088075,9045725,9000135,8950994,8898004,8840879,
     8779258,8712711,8640918,8563495,8480001,8389943,8292787,8188132,8075463,7954250,7823959,7684067,7534074,7373448,7201720,7018508,6823464,6616235,6396708,6164763,5920515,5664157,5396186,5117257,4828285,4530476,4225258,
     3914448,3600118,3284604,2970563,2660793,2358287,2066119,1787317,1524778,1281103,1058511,858696,682723,530974,403084,297988,213982,139088,73021,23732)
x<-30
i<-0.05
f<-function(z,j){
  P<-c()
  for (k in 1:35) {
    P[k]<--z*(1+j)^k
  }
  P[36:70]<-0.5*(1+j)^35
  v<-1/(1+i)
  S<-c()
  for (k in 1:70) {
    S[k]<-P[k]*v^k*l[x+k]/l[x]
  }
  return(sum(S))
}
r<-uniroot(f,c(0,1),j=0.06)$root 
r
j<-seq(0.03,0.07,0.005)
z<-c()
for (k in 1:length(j)) {
  z[k]<-uniroot(f,c(0,1),j[k])$root
}
plot(j,z,type = 'l')