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can someone help me with interval A = x belongs to R and B = (x belongs to R; square root of x^2 = -x) ............ what are the numbers that belong to B please thanks

 Jan 9, 2019
 #1
avatar+98172 
+1

If I read this correctly, the numbers that belong to B are reals and satisfy √ [x^2 ]   =  - x

 

Note that    √[x^2]  is defined as   l x l

 

So.......

 

l x l  = - x        when    x  =   (- infinity, 0 ]

 

 

cool cool cool

 Jan 9, 2019
 #2
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Ok thanks and can you please tell my why, sorry that I posted another question but I wanted to clarify it more.

Guest Jan 9, 2019
 #3
avatar+98172 
+1

Notice that

 

l 0 l  =  - 0   =  0

 

Now....suppose that x is negative

 

So

 

l x  l  =  - x

 

For instance ..... suppose that x = - 3   .....we have......

 

l  -3 l =  - (-3)  =  3

 

 

cool cool cool

 Jan 9, 2019

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