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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: 7,308 Thanks: 2443 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. 

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function, negative, positive, root 
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