Hi everyone,
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I am trying to get a point of intersection between a
polyline and a straight line ?.. and get the x and y coordinates of this point.
For exemplification consider this:
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set.seed(123)
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k1 <-rnorm(100, mean=1.77, sd=3.33)
?k1 <- sort(k1)
q1 <- rnorm(100, mean=2.37, sd=0.74)
q1 <- sort(q1, decreasing = TRUE)
plot(k1, q1, xlim <- c((min(k1)-5), (max(k1)+5)),
type="l")
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ya <- 2
xa = -5
yb=4
xb=12
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lines(c(xa, xb), c(ya, yb), col = 2)
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# I want to get the x and y coordinates of the
intersection of the 2 lines ?.
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m <- (ya-yb)/(xa-xb)
b <- ya-m*xa
ln <- loess(q1~k1)
lines(ln)
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It is clear that the x, y will satisfy both linear
equations, y = m*x + b and the ln polyline ?.. but while I can visualize the
equation of the straight line ? I have problems with the polyline. I will appreciate
any ideas to solve this problem. I thought it a trivial solution but it seems I
cannot see it.
Thanks,
Monica