#I need some clarification on if my workings are correct
1 messages · Page 1 of 1 (latest)
What's the problem Timi? Do you want to check it?
Ok
fäf
You have done this mistake in every problem
Let me tell you the right way to solve the inequality you wrote
fäf
,w (2x+4)/(5x+2) < 1
So you gotta make this right
But the inequality we want is of absolut value
,w -1 < (2x+4)/(5x+2) < 1
@queen oriole see the answer
You made same mistake in all the exercise questions so yeah that need correction
Answer 6 seems wrong too. Exercise 2 seems fine
I don’t understand why the solution to my inequality is wrong
Oh wait. Hold on😂I’m doing the right thing here right?
Wait
We need to first understand if this is clear to you
Answer 6 has two solutions. One in red and one in black. I believe the red one is the right one. Correct?
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
But that's not a sufficient condition
This needs more concern first
I'll ask you an easy inequality question timi
fäf
What's the answer to this according to you? @queen oriole
(-1,0) union (1,infinity)
But I don’t know why this is the answer. Our professor just told us
I'll tell you
Do you know the inequality sign changes when both sides are multiplied by negative numbers
fäf
fäf
Yeah
x>1 you mean?
So we havetwo cases, $x>0 \land 1<x²$ and $x<0 \land 1>x²$
fäf
No I mean x>0
Wait. I meant, x would be > 1. Right?
alright
Where is this? Where are we?
1/x < x gives us 1 > x²
When x is positive
1/x < x gives 1<x²
The inequality depends on the sign of x
Are you confused @queen oriole ?
I’m still a bit confused
Yes
Ok lets go with numbers
Alright
1/-1 < 2 , if I multiply the -1 on both side, I'll get 1 > -2 right
Or will it stay 1 < -2
No
In same way if x is negative and you multiply it on both sides of 1/x < x , what would happen
x (1/x) > x (x) , right?
The sign will change
But why are we dealing with -x?
For this right? x is all values in R?
Yes
Okay. I’m following
If x is negative the sign of inequality will change when we multiply both sides with x
If x is positive the sign of inequality won't change when we multiply both sides with x
2 cases
We have to think about both
We don't have to consider x as some positive number and multiply like 1/x < x gives 1 <x² no
We have to make cases
If x is negative (x<0); 1/x<x imply 1>x
If x is positive (x>0); 1/x > x imply 1>x²
Like this?
No no don't think like that
x takes negative values too right
x=-1,-2,-3 and all
We have to make cases for such values
Which x would be negative?
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
I gtg rn can help you later
Alright. Thank you
@queen oriole has given 1 rep to @icy spire
Just think on this