MHB Absolute Value: Solve for x | MHB

AI Thread Summary
The equation to solve is ||x|-2|+|x+1|=3, with proposed solutions x=0, -2, 2, and -1. The discussion emphasizes the importance of considering different cases for x, such as x<-2, -2<x<-1, -1<x<0, 0<x<2, and x>2. Participants clarify that checking the boundaries is crucial, especially around x=-1, where |x+1| behaves differently. Ultimately, one participant confirms they found the correct answer after considering these cases.
Petrus
Messages
702
Reaction score
0
Hello MHB,
solve $$||x|-2|+|x+1|=3$$
and we find that $$x=0,-2,2,-1$$
I got problem to find the 'case',

Regards,
$$|\rangle$$
 
Mathematics news on Phys.org
Petrus said:
Hello MHB,
solve $$||x|-2|+|x+1|=3$$
and we find that $$x=0,-2,2,-1$$
I got problem to find the 'case',

Regards,
$$|\rangle$$

That doesn't look like the right solution...

Talking about cases, what if x<-2? Or -2<x<-1? And what about -1<x<0? Or perhaps 0<x<2? And x>2?
 
I like Serena said:
That doesn't look like the right solution...

Talking about cases, what if x<-2? Or -2<x<-1? And what about -1<x<0? Or perhaps 0<x<2? And x>2?
I don't mean those are the answer, but those are the point we should check $$\geq$$ or $$\leq$$, I hope you did understand.
Can I also check this one insted of -1<x<0
-2<x<0?

Regards,
$$|\rangle$$
 
Petrus said:
I don't mean those are the answer, but those are the point we should check $$\geq$$ or $$\leq$$, I hope you did understand.
Can I also check this one insted of -1<x<0
-2<x<0?

Sure you can. It's just that |x+1| does something funny at x=-1.
 
I like Serena said:
Sure you can. It's just that |x+1| does something funny at x=-1.
Thanks, got the correct answer now :)
Regards,
$$|\rangle$$
 
Seemingly by some mathematical coincidence, a hexagon of sides 2,2,7,7, 11, and 11 can be inscribed in a circle of radius 7. The other day I saw a math problem on line, which they said came from a Polish Olympiad, where you compute the length x of the 3rd side which is the same as the radius, so that the sides of length 2,x, and 11 are inscribed on the arc of a semi-circle. The law of cosines applied twice gives the answer for x of exactly 7, but the arithmetic is so complex that the...
Is it possible to arrange six pencils such that each one touches the other five? If so, how? This is an adaption of a Martin Gardner puzzle only I changed it from cigarettes to pencils and left out the clues because PF folks don’t need clues. From the book “My Best Mathematical and Logic Puzzles”. Dover, 1994.

Similar threads

Replies
3
Views
1K
Replies
1
Views
1K
Replies
10
Views
2K
Replies
2
Views
2K
Replies
2
Views
2K
Back
Top