Conditions for linear independence

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Homework Statement


Under what conditions on the numbers a and b are the vectors (1,a), (1,b) linearly independent in R2?


Homework Equations





The Attempt at a Solution


x(1,a)+y(1,b)=(0,0)
(x,ax)+(y,by)=(0,0)
(x+y, ax+by)=(0,0)
x+y=0, ax+by=0
x=-y, ax=-by
unsure where to go from here...
 
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what does it mean for two vectors to be linearly independent?

(hint: the answer is NOT:

there exist c1,c2 such that c1v1+c2v2 = 0).
 
Deveno said:
what does it mean for two vectors to be linearly independent?

(hint: the answer is NOT:

there exist c1,c2 such that c1v1+c2v2 = 0).
Good hint!
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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