maths | Mathematics | Page 1

narrow brook Oct 23, 2024, 2:36 PM

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i need help with 2.66 a.
how do i write the expression without the absolute value sign?

pure rivetBOT Oct 23, 2024, 2:36 PM

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narrow brook i need help with 2.66 a. how do i write the expression without the absolute valu...

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mighty cedar Oct 23, 2024, 2:38 PM

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narrow brook i need help with 2.66 a. how do i write the expression without the absolute valu...

you distinguish between x>0 and x <= 0

narrow brook Oct 23, 2024, 2:39 PM

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mighty cedar you distinguish between x>0 and x <= 0

what do you mean, and why?

mighty cedar Oct 23, 2024, 2:40 PM

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consider eq2 |x|+x = 5

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either x is negative, either x is nonnegative

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if x is negative, then |x|=-x, and this implies 5=0, which is absurd, so no solutions for x negative

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if x is nonnegative, then |x|=x, and this implies 2x = 5, so you get x=2.5 >=0 is a solution

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thus, the set of real solutions is x=2.5

narrow brook Oct 23, 2024, 2:45 PM

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yess but how do i write an expression without the absolute value sign?

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could we do a similar task?

mighty cedar Oct 23, 2024, 2:46 PM

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narrow brook yess but how do i write an expression without the absolute value sign?

as I said, you have to distinguish with the sign of x

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try to do the third one

narrow brook Oct 23, 2024, 2:46 PM

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mighty cedar try to do the third one

b?

mighty cedar Oct 23, 2024, 2:46 PM

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c

narrow brook Oct 23, 2024, 2:47 PM

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okok

narrow brook Oct 23, 2024, 2:49 PM

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mighty cedar c

x = -5/2

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right?

mighty cedar Oct 23, 2024, 2:50 PM

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no

narrow brook Oct 23, 2024, 2:50 PM

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ohhh

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i see

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because if x is negative

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then |-x| will be positive

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but the other x is still negative

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so there is no solutions for x?

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on c

mighty cedar Oct 23, 2024, 2:52 PM

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you're right, there are no solutions

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on c

narrow brook Oct 23, 2024, 2:52 PM

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yess

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is this incorrectly shown then?

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what have i done wrong?

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i know that the answer is wrong but why did i still get x = -5/2?

mighty cedar Oct 23, 2024, 2:54 PM

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narrow brook what have i done wrong?

to get line 2,you need to assume that x>=0

narrow brook Oct 23, 2024, 2:54 PM

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mighty cedar to get line 2,you need to assume that x>=0

of course, you are right

mighty cedar Oct 23, 2024, 2:55 PM

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so anything you deduce after, you always have x>=0, and -2.5 is not positive

narrow brook Oct 23, 2024, 2:55 PM

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correct

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ok i will do the task all over again

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but do u have any similar tasks that u would recommend me to do?

mighty cedar Oct 23, 2024, 2:57 PM

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there should be other exercises involving the absolute value in your book

narrow brook Oct 23, 2024, 3:00 PM

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mighty cedar there should be other exercises involving the absolute value in your book

well there arent many

mighty cedar Oct 23, 2024, 3:01 PM

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then ask your teacher or google them

narrow brook Oct 23, 2024, 3:02 PM

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mighty cedar then ask your teacher or google them

okok

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thanks for the help

narrow brook Oct 23, 2024, 4:31 PM

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+close

winged mantleBOT Oct 23, 2024, 4:31 PM

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narrow brook +close

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