[R] optimize

[Muhammad Rahiz]

Hi all,

I'm trying to get the value of y when x=203 by using the intersect of 
three curves. The horizontal curve does not meet with the 
other two. How can I rectify the code below?

Thanks

Muhammad

  ts <- 1:10
  dd <- 10:1

  ts <- seq(200,209,1)
  dd <- c(NA,NA,NA,NA,1.87,1.83,1.86,NA,1.95,1.96)

  plot(ts,dd,ylim=c(1.5,2))
  abline(lm(dd~ts),col="blue",lty=2)
  abline(v=203,col="blue",lty=2)

  xy <- lm(dd~ts)
  fc <- function(x) coef(xy)[1] + x*coef(xy)[2]
  val <- optimize(f=function(x) abs(fc(x)-203),c(1.5,2))
  abline(h=val,col="blue",lty=2)