#i need help in understanding these
civic tapirBOT
boreal horizon
<@&286206848099549185>
They are asking to solve f(x)>-4
And i just want to ask why is it not (-4;+infinity)
And why is it ა)
scarlet sky
And i just want to ask why is it not (-4;+infinity)
Why should it be (-4; infinity)?
What about at x = -5?
Is f(x) really not > -4 there
boreal horizon
It says solve f(x)>-4
scarlet sky
Yes
boreal horizon
Yea and why is it (-infinity;0)U(0;+infinity)?
scarlet sky
f(x) is shown in the graph
At e.g. x = 2, f(x) is equal to 0
At x = -2, f(x) is equal to 0
And so on
scarlet sky
Basically the question asks "on which interval does this graph lie above the line -4"
You can draw in the line y = -4 as the red line
Well, then the answer is "Everywhere, except at x = 0, because there, f(x) is exactly = -4, not > -4"
scarlet sky
Yeah
boreal horizon
Why?
scarlet sky
You are looking for the interval for which f(x) >= 3
So you are looking at where the graph lies above the line y = 3 or has a value equal to it
boreal horizon
Its none
scarlet sky
Well, nowhere except that at x = 0, it is exactly on the red line
And since we are looking for f(x) >= 3, x = 0 fulfills it
boreal horizon
So to solve these issues i just have to make a parallel line of x and then solve it
Is there any youtube tutorial vids so i can understand it better
One question i still have is that in first photo its just fliped function of second photo i gave its just that one has -2 and 2 and second has 3 and -3 but why doesn’t it have same answer as first
scarlet sky
One question i still have is that in first photo its just fliped function of sec...
It's not exactly flipped
The zeros of the first graph are at x = -2 and x = 2. The zeros of the second are at x = -3 and x = 3.
If it was just flipped, those would be the same zeros
scarlet sky
So to solve these issues i just have to make a parallel line of x and then solve...
Yeah, you basically just look at where the y-values of the graph are higher (or lower, depending on the exercise) than the given one
It can help to draw in the line like I did
boreal horizon
i don't want to be annoying and all but i still don't get why its still ა)
scarlet sky
But you don't need to do that
boreal horizon
after drawing what should i imagine
boreal horizon
then?
scarlet sky
We are looking at where the graph is higher (in y-direction) than the line
boreal horizon
higher then -4 is -3 -2 -1 and etc right?
scarlet sky
/Where the graph is above the line
scarlet sky
higher then -4 is -3 -2 -1 and etc right?
I mean the y-values
The line has the y-value -4 everywhere, right?
boreal horizon
yea
scarlet sky
The graph has the y-value 0 at x = 2, right?
boreal horizon
yes
boreal horizon
yea
scarlet sky
So yeah, this is basically what we do. We look at the y-values of the graph
Everywhere, they are greater than -4
Except at x = 0
Because the graph has the y-value -4 at x = 0 too
Just like the line
And we are looking at where the graph has y-values larger than the line
So we can say f(x) > -4 is fulfilled for all numbers except 0
And you can denote that as (-infinity, 0) u (0, infinity)
I will be gone for now. Usually, the help channels are more active than the forum, by the way.
boreal horizon
oh if lets say in function they asked f(x)>-3 then line would be greater then -3 except at x=0? same goes for if they said f(x)>4
scarlet sky
If they said f(x) > 0 and we had the same graph, it would be (-infinity, -2) u (2, infinity)
The y-value is larger than 0 for all x < -2
And for all x > 2
boreal horizon
thanks, you made me understand functions a bit better
scarlet sky
I will be gone for now, just for the future: It's probably better to ask in a unoccupied help channel (like #help-18) instead of the forum, those are more active
Bye!
boreal horizon
.close