search for: 1.732051i

Mirando los comentarios, realmente lo que deseo es encontrar la raíz real de (-0.5)^(1/5) la cual debería ser -0.87055056329. José me hace caer en cuenta que además de no encontrar la raiz real, tampoco da todas las raiz complejas. Habría alguna manera de que tuviera en cuenta? > ------------------------------ > > Message: 6 > Date: Thu, 15 Oct 2015 11:25:39 +0200 > From: José

El problema del módulo es que pierde el signo. En tu caso sale igual porque has invertido el signo del coeficiente en el polinomio (en realidad se me pasó a a mí advertir que el término independiente debe ir con signo negativo): .> polyroot(z=c(0.5,0,0,0,0,1)) [1] 0.7042902+0.5116968i -0.2690149+0.8279428i -0.2690149-0.8279428i [4] 0.7042902-0.5116968i -0.8705506+0.0000000i .> .>

Why does the expression "(-8)^(1/3)" return NaN, instead of -2? This is not answered by http://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-are-powers-of-negative-numbers-wrong_003f Thanks, Dave [[alternative HTML version deleted]]

No sé si he entendido bien la pregunta, pero creo que lo que quieres obtener es esto: (as.complex(-0.5)^(1/5)) Saludos,Salva > To: r-help-es en r-project.org > From: canadasreche en gmail.com > Date: Thu, 15 Oct 2015 10:45:10 +0200 > Subject: Re: [R-es] potencia fracional de un número negativo > > Hola. > No sé si va por aquí, pero prueba a quitar el paréntesis a (-0.5) >

This is some interesting: > -8^(1/3) [1] -2 > x=(-8:8) > y=x^(1/3) > y [1] NaN NaN NaN NaN NaN NaN NaN NaN 0.000000 1.000000 [11] 1.259921 1.442250 1.587401 1.709976 1.817121 1.912931 2.000000 So, can anybody explain this?! (Why is x[1]^(1/3)=y[1]=NaN, but -8^(1/3)=-2?) Thx!!! [[alternative HTML version deleted]]

hi all why does R do this: (-8)^(1/3)=NaN the answer should be : -2 a silly question but i kept on getting errors in some of my code due to this problem. i solve the problem as follows: say we want : (-a)^(1/3) then : sign(a)*(a^(1/3)) works but there has to be a simpler way of soing such a simple mathematical operation. thanking you / allan

Hello, I use R a lot, one thing bugs me is that when I try the following > x<- -8 > x^(1/3) [1] NaN However, it is fine with -8^(1/3). Priority goes to the power. Can you help me out for this? Thanks. Best, Zhiyuan J. ZHENG Ph.D. Candidate Economic Department Virginia Polytechnic Institute and State University Phone: 540-231-5120 , Blacksburg, VA, 24060