[R] solve scalar linear equation

[message]

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?

> 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?