Re: [R] solve scalar linear equation
On 2014-05-20 10:00, r-help-requ...@r-project.org wrote: -- Message: 32 Date: Mon, 19 May 2014 23:04:27 +0100 From: Rui Barradas ruipbarra...@sapo.pt To: message let...@openmailbox.org, r-help@r-project.org uniroot(function(x) 5*x - 55, c(0, 20)) Why does this instruction fail if the interval is changed? 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 __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] solve scalar linear equation
On 22-05-2014, at 12:28, message let...@openmailbox.org wrote: On 2014-05-20 10:00, r-help-requ...@r-project.org wrote: -- Message: 32 Date: Mon, 19 May 2014 23:04:27 +0100 From: Rui Barradas ruipbarra...@sapo.pt To: message let...@openmailbox.org, r-help@r-project.org uniroot(function(x) 5*x - 55, c(0, 20)) Why does this instruction fail if the interval is changed? 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 See the Details section of the uniroot documentation. Berend __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] solve scalar linear equation
Hello, Because there is no root of that function in the interval c(0, 10). Just like the error message says. Rui Barradas Em 22-05-2014 11:28, message escreveu: On 2014-05-20 10:00, r-help-requ...@r-project.org wrote: -- Message: 32 Date: Mon, 19 May 2014 23:04:27 +0100 From: Rui Barradas ruipbarra...@sapo.pt To: message let...@openmailbox.org, r-help@r-project.org uniroot(function(x) 5*x - 55, c(0, 20)) Why does this instruction fail if the interval is changed? 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 __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] solve scalar linear equation
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? __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] solve scalar linear equation
Hello, See inline. Em 22-05-2014 13:35, message escreveu: 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's not. This is basic Math. 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? I believe that Berend was trying to have you read that The function values at the endpoints must be of opposite signs (or zero), for extendInt=no, the default. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] solve scalar linear equation
On 22-05-2014, at 14:35, message let...@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 __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
[R] solve scalar linear equation
Readers, The function 'solve' states that it is applicable to a vector or matrix object. Please what is the syntax to solve a very simple equation like: 5x + 1 = 56 The books read so far give explanations for simultaneous linear equations or differential equations, but there have not been able to find a very basic description to solve simple equations (as an initial learning stage). Thanks. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] solve scalar linear equation
Hello, Try ?uniroot instead. Your equation is equivalent to 5x - 55 = 0, so the instruction would be uniroot(function(x) 5*x - 55, c(0, 20)) Hope this helps, Rui Barradas Em 19-05-2014 14:46, message escreveu: Readers, The function 'solve' states that it is applicable to a vector or matrix object. Please what is the syntax to solve a very simple equation like: 5x + 1 = 56 The books read so far give explanations for simultaneous linear equations or differential equations, but there have not been able to find a very basic description to solve simple equations (as an initial learning stage). Thanks. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
