solve scalar linear equation
On 22-05-2014, at 14:35, message <letter at openmailbox.org> wrote:
On 2014-05-22 11:00, Berend Hasselman wrote:
uniroot(function(x) 5*x - 55, c(0, 10))
Error in uniroot(function(x) 5 * x - 55, c(0, 10)) : f() values at end points not of opposite sign
I don?t believe this. The error message says it all. 5*0-55 ==> -55 5*10-55 ==> -5
The error states "opposite sign", which suggests to a rudimentary novice that end points (0 and 10, or 0 and 20) must give results of the function such that one value is negative, another value is positive. Or is this interpretation wrong?
No. It is exactly what the error message says. Both function values are negatieve i.e. not of opposite sign. Which is why you got the error message.
See the Details section of the uniroot documentation.
The documentation states that the upper end point (in this example 10, or 20) must be strictly larger than the lower point (0). What is being mis-understood please?
Read the sentences after the first. Berend