#I need some clarification on if my workings are correct

1 messages · Page 1 of 1 (latest)

queen oriole
icy spire
queen oriole
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Yes please

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As well as these too if possible

icy spire
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Ok

primal plazaBOT
icy spire
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You have done this mistake in every problem

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Let me tell you the right way to solve the inequality you wrote

primal plazaBOT
icy spire
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,w (2x+4)/(5x+2) < 1

icy spire
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So you gotta make this right

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But the inequality we want is of absolut value

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,w -1 < (2x+4)/(5x+2) < 1

icy spire
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@queen oriole see the answer

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You made same mistake in all the exercise questions so yeah that need correction

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Answer 6 seems wrong too. Exercise 2 seems fine

queen oriole
queen oriole
icy spire
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Wait

icy spire
queen oriole
icy spire
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The thing given in red is about sequence as far as I can see, for a series to be convergent it's sequence must be convergent to 0

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But that's not a sufficient condition

icy spire
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I'll ask you an easy inequality question timi

primal plazaBOT
icy spire
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What's the answer to this according to you? @queen oriole

queen oriole
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(-1,0) union (1,infinity)

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But I don’t know why this is the answer. Our professor just told us

icy spire
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Do you know the inequality sign changes when both sides are multiplied by negative numbers

primal plazaBOT
icy spire
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But this only holds for x>0

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What about x<0

primal plazaBOT
queen oriole
icy spire
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So we havetwo cases, $x>0 \land 1<x²$ and $x<0 \land 1>x²$

primal plazaBOT
icy spire
queen oriole
icy spire
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Aka When x is positive

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Wait

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We make two cases alright

queen oriole
icy spire
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In first case x is negative and in second case x is positive

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So when x is negative

queen oriole
icy spire
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1/x < x gives us 1 > x²

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When x is positive

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1/x < x gives 1<x²

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The inequality depends on the sign of x

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Are you confused @queen oriole ?

queen oriole
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I’m still a bit confused

queen oriole
icy spire
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Ok lets go with numbers

queen oriole
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Alright

icy spire
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1/-1 < 2 , if I multiply the -1 on both side, I'll get 1 > -2 right

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Or will it stay 1 < -2

queen oriole
icy spire
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In same way if x is negative and you multiply it on both sides of 1/x < x , what would happen

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x (1/x) > x (x) , right?

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The sign will change

queen oriole
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But why are we dealing with -x?

icy spire
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x is not just positive, it takes all values in R

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It can be negative or positive too

queen oriole
icy spire
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Yes

queen oriole
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Okay. I’m following

icy spire
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If x is negative the sign of inequality will change when we multiply both sides with x

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If x is positive the sign of inequality won't change when we multiply both sides with x

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2 cases

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We have to think about both

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We don't have to consider x as some positive number and multiply like 1/x < x gives 1 <x² no

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We have to make cases

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If x is negative (x<0); 1/x<x imply 1>x
If x is positive (x>0); 1/x > x imply 1>x²

queen oriole
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Like this?

icy spire
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No no don't think like that

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x takes negative values too right

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x=-1,-2,-3 and all

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We have to make cases for such values

queen oriole
icy spire
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When x is negative meaning x takes values like -1 or -2 , in that case if we multiply x on both side the sign of inequality will change cuz it's negative

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I gtg rn can help you later

queen oriole
queen oriole
fading oasisBOT
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@queen oriole has given 1 rep to @icy spire

icy spire
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Just think on this