
PreCalculus PreCalculus Math Forum 
 LinkBack  Thread Tools  Display Modes 
April 30th, 2017, 07:07 PM  #1 
Newbie Joined: Apr 2017 From: philippines Posts: 1 Thanks: 0  is it possible for a function to have a positive or negative root?
sorry im not really good at math please don't judge me for example f(x)=(cuberoot)x+8 is it still a function if for some instance it was f(x) = positive or negative cuberoot of x + 8. Well i have not seen any example with that positive or negative cube root or square root so maybe the answer is no but why? I wondered be when i was studying function inverses is was possible for a function to have inverse relations say for example s=16(t2)^2 when you get its inverse it will be an inverse relation t=2 (positive or negative squareroot of 68s/4) here positive and negative square roots where applied ....and i want to know why? what was the basis of doing that? I hope you get my point im very confused right now .... 
April 30th, 2017, 07:32 PM  #2 
Math Team Joined: Dec 2013 From: Colombia Posts: 6,778 Thanks: 2195 Math Focus: Mainly analysis and algebra 
The is only one (real) cube root of a real number. For example, $\sqrt[3]{8} = 2$ and that's the only (real) answer. $\sqrt[3]{8} \ne 2$ because $(2)^3 = 8$, not $+8$. With square roots, if there can be two real numbers that satisfy the equation. 

Tags 
function, negative, positive, root 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Why did this change from positive to negative  Opposite  Algebra  2  September 17th, 2014 09:27 PM 
Manipulation of negative square root of a negative term/#  daigo  Algebra  3  June 30th, 2012 07:06 AM 
How do you know if it is positive or negative infinity?  SSJBartSimp  Calculus  1  June 11th, 2012 10:56 AM 
Positive and negative results  Ockonal  Calculus  5  December 4th, 2011 08:04 PM 
Positive and negative angles  David_Lete  Algebra  3  April 9th, 2009 05:03 AM 