#help-23
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I'm not sure how to solve this type of thing
First consider $ \lim_{x \to \frac{\pi}2} \cot (2x) $
Thanks
$$ \lim_{x \to \frac{\pi}2} \cot (2x) $$
rysrobrgldvoelrđťep>vneae=u
I meant this
Your limit exists if this limit exists
Because the exponential function is continuous, so you would be able to move the limit inside the exponent if it exists
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How would I solve this problem
Lhopital is a good choice
How do you find the derivative of sin4x?
what is derivative of f(g(x))
Ah i see
What this part then
I'm unsure how I'm supposed to simplify the right button part
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in piecewise functions, how do boundary inequalities (ie. 0 < x < 1) dictate which type of endpoint circle to use?
endpoint circles are based on whether the value is inclusive or not
if the value is included (so having a less than or equal to sign for example) you have a filled in circle
if the value is not excluded (like the number 5 in the set x<5) then you use a non filled in one
ohh
can endpoint circles dictate which is part of graph
like for example, the shaded endpoint of slope 1 and the open endpoint circle of slope 2
my classmate said you can use vertical test and horizontal test to check if they are parallel (i think)
yes. if these points are different for an input value you have what is called a discontinuous function
can you show me a photo of what you mean i think i might be confusing it haha
yeah so here you can see
the function is defined for all of the values of x less than equal to 1 and more than equal to 2
but isnât defined in betweeb
so that means
functions can only really be parallel as long as youâre describing a linear function because they have constant gradients
here both graphs are parallel because you can see the coefficient of the x term is the same (0 for both cases)
if you look at the right hand side, there is no x value in it
if i had a function as say 5x + 4
ahhh that makes sense
that would have an x term with coefficient 5
here there is no x term so the coefficient is 0
yeah
also, how do i find the domain and range for this? i have the function expressions already, idk how to do the domain range
@twin prawn Has your question been resolved?
so look at the function here
what are the range of values that you can see along the x and y axis
along x youâll see it is fully defined from -7 to 7 with only a hole at the-1
and for y itâs defined at 6, from 5 to -1 (including -1 but not including 5)
a hole at -1 means its not included?
yes exactly
so therefore,
as you can see both the piece wise functions that go close to x =-1 have blank circles
theres going to be unions
which means they donât
yes exactly
you can express it as [-7,-1) U (-1,7]
if youâre using set
notation
ohh
question
idk how to word this
but if shaded circle dictates inclusion, whilst unshaded dictates exclusion, if the shaded and unshaded become parallel to each other, does the unshaded circle become part of the line/slope/shape with the shaded circle?
cause our teacher taught us that shaded and unshaded connect each other
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Hi guys, probably basic question but
I don't see my answer in any of this lol
average rate of change is literally the secant line connecting day 1 and day 14 point right
,, A(x) = \frac{f(b) - f(a)}{b-a}
ćĺ°ĺ§ż
it looks like (21-11)/(14-1) to me
Result:
0.76923076923077
What am i missing?
nothing?
but where's my answer lol
0.65 obviously
don't you think?
i've never come across a question where the "closest" part is that far off
it doesn't seem strange, you should come across this in the future
okay fair enough
one more thing
or a couple maybe đ
I solved this question by finding the slope through implicit differentiation ofc
which is b/a
so it's between D and E and i just plugged in x = (b+a) and looked at which of them returned (b-a) so the answer is E ig
had a bit of trouble actually making that formula though
,w equation of line passing through (b+a,b-a) with slope b/a
through (b+a,b-a),slope is b/a then the line is
$y = \frac{b}{a} (x-(b+a))+(b-a)$
ç§ć°´
oh yeah the y - y1 = m(x-x1) formula right?
idk why i lack the most obvious observations
yes
thanks
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Can you use the well-ordering property to prove the statement: âEvery positive integer can be described using no more than fifteen English wordsâ?
that makes no sense
i mean the statement, there's a finite amount of 15 word sentences
Yeah. You can assume the words come from a particular dictionary of English
i dont see whats the problem with that
the problem is you can't pointat at every number uniquely
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Hia
I have one possible position vector, being
(9,3)
How can there be one more position????
that's it
hm ok i wasnt seeing it either but plotting the points it does work: (blue are the given ones and red are the solutions)
seems like the red points form a triangle with the blue points at the midpoints of the segments of the triangle, kinda cool
yeah
anyway what you would do is pick different pairs of the original 3 points and then build the 4th point similar to how you did
Maybe you can fit 4 blue triangles in the red triangle
youll get different solutions if you pick the different pairs and also extend in different directions
yes, that is accurate in fact : )
welcome
ok badly drawn but
its just similar triangles really, the small ones are similar to the overall large one (same angles, measures divided by 2)
Oh
just stretched out but exact same angles, thats what similar triangles are
Oh yeah, right to scale is same angles
But lengths differ
Jajaajaj
Cool
Thanks for pointing that out
and it makes sense that 4 small ones fill the large one since
Area of large one is: 1/2bh (one half base times height, just regular area of a triangle right?)
Yes
since small ones sides measure half the area would be:
1/2(1/2b)(1/2h)
=1/8bh
so 1/4 of the large one
:p
kinda every problem in geometry you can just draw triangles everywhere and see all this random stuff, its all very interconnected haha

but seriously, just start drawing random triangles between points when you are confused on how to solve a geometry problem
starts with a circle and some points? great, draw triangles
a rhombus and some points? great, draw triangles
lol ok good luck : )
well you dont have ti visualize it, you can draw it on paper and actually look at it
đ
or screen
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if i have a matrix
Me too
does the colums then span R^3
By definition yes
The rank of a matrix is the dimension of the space generated by the columns
Whether it's 5x4 or 78x43
how about the rows
Identical
what about in total?
I believe 3 columns would be linearly independent, yes
no, they span a 3 dimensional subspace of R5 since the columns are a subset of R5 not R3
i mean you can have an isomorphism to R3 but still : )
but the entire matrix
or ratherthe colums are they linearly idependent
of a rank 3 matrix? only 3 of the columns
thats what definition of rank is, like Nel said
rank 3 means both the column space and row space have a dimension of 3, thats a result proven in LA
All the columns can't, since there are more than 3
so if we have a 4x5 matrix with rank 3
then you can find 3 rows or colums that are linearly independent, and the rest of the rows and colums can be expressed as a linear combination of those 3
therefore the colums are not linearly independent
Yes
or?
ya
is that better?
if you are talking about a square matrix n x n
question 4 and 5, what are they even asking
then its rank determines whether its invertible or not, maybe thats what youre thinking of, not linearly independent
any 1 matrix other than the 0 matrix is linearly independent as far as the vector space of m x n matrices it is part of i guess, but thats not really related to what you were talking about with the columns
There are no question numbers in your picture
from 1-6
so Bx = 0 relates to the kernel of the matrix
it starts with 1, which is colums span r^5.
the last is question 6 (none of the above)
the one that would be true is Bx = 0 has infinitely many solutions
since the kernel's dimension > 0 right?
If the rank is less than the number of columns (and rows), then you have more unknowns than equations
So yeah that would be infinitely many solutions
i havnet heard of kernel yet
well think of it this way
5 columns, 4 rows, right?
yh
So you can multiply a vector with 5 elements
i will have x1,x2,x3,x4,x5
5x4 matrix implies 5 rows 4 columns actually
So yes you would have 5-rank = 5-3=2 free variables
so its going from R4 -> R5
the kernel and rank i think should add up to the dimension of the domain (4) so dim(kernel) = 1 which is just 1 free variable
isnt it that way?
Yeah that's 4 columns, 5 rows
yep so its R4 - > R5 transformation
My bad then, but same thing: you would have 4-rank = 1 free variable
so still infinitely many solutions
same answer regardless if it is 4x5 or 5x4 i guess
so what basically happens is...the domain has 4 dimensions, 3 of those are used to map to a 3 dimensional space in the range...and the leftover dimension maps to 0 (i.e. solutions of Bx = 0). it turns out that the values that map to 0 are also a vector space
dim (kernel) + dim (rank) = dim (domain)
1 + 3 = 4
something like this, im actually a little bit confused by the non square matrices and rusty but i think its the dimension of the domain they add up to? đ¤
that we have 5 four dimensional vectors
5x4 means you can multiply it by a 4x1 column vector and get a 5x1 column vector so that just should make you think of it as a R4 -> R5 transformation
The kernel is the subspace of the domain mapped to zero
Sounds right to me
so if your dim(kernel) = 0 then Bx = 0 will have a single solution...the zero vector
and everything else doesn't give 0
but the statement Bx = 0 has 0 solutions will never be true (5th statement in your list) because there will always at least be the trivial solution of x = 0 vector
even for a matrix with maximum rank
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how do i start ? without using lhopital
Do you know the limit as x goes to 0 of sinx/x
1
How about x/sinx
(... 1?) not that sure
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"An urn contains 3 numbered balls (1, 2, and 3). First, a ball is drawn from the urn. If ball "k" is drawn, "k" pieces are selected with replacement from a batch containing 60% defective pieces. Let X be the number of defective pieces in the sample."
Find the set of possible values of X and its probability function.
I don't know how to start solving this exercise
well we're going to end up drawing either 1, 2, or 3 pieces from the batch right?
so I guess there is potential also for drawing either 1, 2, or 3 defective pieces
If ball 1 is drawn, 1 piece is selected. Then in this case we have P(X = 0) = 40% and P(X = 1) = 60%? Or should I multiply 1/3* 40% and 1/3* 60%?
yep
đ¤ 1/340%? where are you getting that? what you said in the first part of that sounds good
1/3*40%
oh lol
well, let's just think of each individual case we'll worry about the 1/3 at the end i'd say
so what about if you pull ball 2, then there's potential for X = 0, X = 1 or X = 2
how about X = 1? 0.6*0.4?
so we can get 1 in two ways for that case, either by pulling a defective piece first and then a good one, or the other way around
so it would be 0.6 * 0.4 + 0.4 * 0.6, or just twice what you said
got it, then the X = 2 would be just 0.6^2
yup
X = 2**
we can double check our work for ball 2 case makes sense by making sure all the numbers add up to 1
so 0.16 + 0.48 + 0.36 = 1 so it looks good : )
got it, now i can do it with ball 3
yap
sorry, what?
Should I take into account the probability of drawing each ball? There are 3 balls, ball 1, ball 2 and ball 3. Each one has a 1/3 probability of being drawn
we can handle all that at the end by just multiplying the total by 1/3. let's keep doing the same pattern as the other cases without jumping the gun, for ball 3 we'll have possibilities X = 0, X = 1, X = 2, X = 3 right? so let's start with X = 0 like the other ones
sure, X = 0 would be 0.4^3
yeah
X = 1 = (0.6 * (0.4)^2)*3
sounds right
yeah, so maybe multiply those out real quick, write them out here and double check they add up to 1
ball 1: X=0: 0.4, x=1: 0.6
ball 2: X=0 0.16, X=1: 0.48, X=2:0.36
ball 3: X=0: 0.216 X=1: 0.064 X=2: 0.432 X=3: 0.288
alright so now overall we can add up each X = 0, X = 1 etc. cases and multiply by 1/3 the total like you said (saves the work of multiplying every number by 1/3, we can just multiply the added totals)
so for X = 0 we have: P(X=0) = ( 0.4 + 0.16 + 0.216 ) / 3
etc. and that should be about it
does that make sense?
oh got it now
it is easier than i thought
thanks @shadow glade, i will finish it and maybe come back later with other questions
thx
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wdym 1-1
What is injective
i am not sure but i found 2 answers and i dont know wich one is correct
one that m<=0
and the other one m>=0
somehow if m>=0 the function isnt injective
Injective means if we have two different inputs weâd have two different outputs
Your function is a parabola
Go on Desmos and play with slider for m
That might give you the intuition
i already have the intuition but i can work in two different ways and get different answers
But this just means itâs injective in a given interval if the function is one to one
Show me your work
so
x1,x2 is from R
with f(x1)=f(x2)
(x1)^2+mx1-1=(x2)^2+mx2-1
fast forward and i get
(x1-x2)(m+x1+x2)=0
x1-x2=0
=> x1=x2=0
=> injective
m+x1+x2=0
=>
m>=0
@jaunty finch Has your question been resolved?
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how do i get help
this channel is yours, so you just ask your question
i have 5 questions is that ok
usually just ask one at a time
then when you're done you can either close and open a new one or if it's short enough, use the same channel
options are positive negative undefinded and zero
so how do you know if they r any of these
its negative
zero=no change
yeah?
yeah
Take two points on the graph.
(X1,Y1) and (X2,Y2)
Slope = (Y2 - Y1)/(X2-X1)
i wanted to say this for the first but seems like i was fashionably late
yes i dont even know what im looking at
X1 is a number
Y1 is also a number
(X1, Y1) is a pair of numbers
Called a coordinate pair
ahh
that makes sense
you didnt learn this formula and the teacher gives these problems?
No i just forget everyting
can u help me on this
Use the formula you were given
You have two points
Plug it into the formula
write it down multiple times
Use the formula
And coordinates are (x, y), meaning you need the parentheses
repeat the steps here
You have two coordinates, label what x1, x2, y1, and y2 are then plug them into the formula
Yes
Use the formula in this image, plug in those values you just labeled
No that's not the formula
fuck
The $m = \frac{y_2 - y_1}{x_2 - x_1}$ part
CaptainNova22
You labeled what x1, x2, y1, and y2 are
You just need to plug them into that formula
Yes
Did you get a negative?
Then why are you questioning about a negative if you didn't get one
If you didn't get a negative, then why would you question about it?
Are you just going to throw on a negative?
You should be confident in your math skills
If 6 - 2 = 4 and 4 - -7 = 11, and neither values have a negative, why would you ask if it's negative
As asked, are you just going to randomly make one of those numbers negative?
No
Then it's not negative
@slender nexus Has your question been resolved?
actually im done
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Hi, so im currently dealing with the prove of the existence of a fixed point on a monotonically increasing function f:[0,1]â[0,1]
What i dont get here is:
how can f(s) be greater than s, if s is the supremum?
how does this lead to f(x) <x ?
well thats the question, can f(s) > s?
turns out, no
because then there is some x between them
s < x < f(s). but because x > s we then need f(x) < x
so f(x) < x < f(s), so f(x) < f(s)
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what does the big theta symbol mean
Please show the original problem, exactly as it was stated to you, with the entire original context. A picture or screenshot is best. If the original problem is not in English, then post it anyway! The additional context might still be helpful. Do your best to provide a translation.
@inland salmon Has your question been resolved?
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Need to solve when t is approaching 0. Every app Iâve used said the answer is 1 but I canât see how they got there. Help please đ
,rccw
I need to get rid of that t in the denominator and the t^2 in the numerator
Well also bear in mind that as t^2 + t = t(t + 1), to common denominator them, you only need to multiply 1/t by (t+1)/(t+1)
Also what happened here?
oh my I missed that
okay so should I have factored it to t(t+1) at the beginning?
That would have made your life much easier 
I see can I try that and get back to you or should I close this channel?
But if you didn't, you have here that the last line is $\lim_{t\to 0 }\frac{t^2}{t^2(t + 1)}$ when you factor the bottom
@junior smelt
Sure thing, you can keep this open and @ me when you get it 
,rccw
,rccw
I think it looks good and also should I be using the notation "Lim" notation after every step?
Also the previous hint was that you'd have that
\begin{align*}
\frac{1}{t} - \frac{1}{t^2 + t} &= \frac{1}{t} {\color{orange} \frac{(t + 1)}{(t + 1)} } - \frac{1}{t(t + 1)} \
&= \frac{t + 1}{t(t + 1)} - \frac{1}{t(t + 1)} \
&= \frac{t + 1 - 1}{t(t + 1)}
\end{align*}
then that's easier to simplify \holothink
@junior smelt
Okay I see
So when im finding a common denominator I dont have to multiply both sides
that makes my life a whole lot easier
yea this has definitely opened my eyes thank you so much @junior smelt
Yep, you just need to "make up" the terms to get the denominantors all being the same really!
And a pleasure 
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Hi, idk how to solve 15, if you can help me, thanks a lot.
Statement : In this part, we look for functions f defined and derivable on I (with I an open interval of R containing 0) that verify: f(x) + f(y) = f((x+y)/(1-xy))
Let f be a function that satisfies these hypotheses.
14.calculate f(0) (I found f(0)=0)
15. let, aâI with aâ 0
determine Îť>0 as for all hâ[-Îť;Îť], the equation
a+h = (a+y)/(1-ay), (of unknown y) admits exactly one solution. This solution is denoted y(h). Then show that h->y(h) is derivable on [-Îť;Îť]. Calculate y(0) and y'(0)
I have several leads but nothing comes to fruition.
I first thought about solving this equation :
(a+h)(1-ay)=(a+y) which brought me back to a 2nd-degree equation, but I don't think that was very helpful (or idk how to deal with it)
Then, as the lim of (a+y)/(1-ay) is -1/a
So I thought it was sufficient to choose lambda small enough so that [a - lambda, a + lambda] does not contain -1/a. But what lambda?
Or I thought as [-Îť;Îť] is '' symmetrical '' it contains 0 so we can choose h=0 but with this method I can't conclude about the possible value of lambda...
I'm stuck here, so if someone could help me out đ
(the goal of the problem is to find the arctan function so lambda should be equal to pi/2??)
Thanks
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Hi is there anyone that know how to work out this exercise
What does tgh represent?
i assume tanh
If thatâs the case, what are you allowed to use to evaluate limits OP?
Have you written tgh in terms of powers of e?
no how can I do it
Do you know any limits involving tgh(x)?
there is no need for writing it that way btw
It comes down to proving that the limit of tanh(x)/x as x goes to 0 is 1
@orchid agate
but I do not understand how can we use tanh(x)/x as x goes to 0 is 1 when original limit goes to infinite
It would mean that (x + 2) * tanh(1/(x + 2)) would go to 1 as x goes to infinity
And with that you can multiply the top and bottom of the original limit with (x + 2)
the denominator could be simplified then
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so the answer is correct but not in correct form since i have to rationalize the root in the denominator , but i dont have any idea on how the example did it
basically you have the form of (a+b) in the denominator, then you can square both a and b by multiplying it by (a-b) because a^2 - b^2 = (a-b)(a+b)
so you multiply the fraction by (8 -15sqrt(3))/(8 -15sqrt(3)) since it doesnt change the value of the fraction
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can you check the calculations and si units
,w 2*.071591/(997.04799.806.008)
Thank you!
@mortal sandal is my si units correct?
ping me when you respond
<@&286206848099549185>
@latent tendon Has your question been resolved?
Yep seems so (though I think you meant m/s^2 here)
Can some one help me
@latent tendon Has your question been resolved?
yes!
can you check this
i guess im just concern why my calculations are correct is bc my graph looks odd
and my data differs from my friend
<@&286206848099549185>
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from the integral we have ysqrt3<x<sqrt(1-y^2)
why do we use x= ysqrt3 instead of the upper bound?
wdym by upper bound
x= sqrt(1-y^2)
you mean when solving for theta or...?
that's equivalent to r = 1
which is true for the unit circle
like you can't solve for theta
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Help
can u see u private
what-
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what
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desperately need help on this homework
Solve Ax=0
I've got no idea how even to do that
Make an augmented matrix. Do you know how to do that?
no unfortunately.. Ive been using apps to help the whole semester and they arent working anymore đ
math is not my strong side
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Hi there, attached is a picture from a problem sheet im working on. It is asking to obtain the power series solution the ODE shown. I have found X=0 to be a regular singular point and proved such with XP(x) and X^Q(x) . but when It comes to finding the solution by frobenius I am stuck as all I get is A_n being = to 0. I will attach some work also
X^Q(x) . but when It comes to finding the solution by frobenius I am stuck as all I get is A_n being = to 0. I will attach some work also
I would appreciate any help in finding a solution!
Some of my workings
In any other example problem I have completed, the powers of X in each summation were different requiring me to change them thus casuing a change in A_n, due to the coefficients here making all the powers the same Im not sure how I can solve
@cinder violet Has your question been resolved?
<@&286206848099549185>
Anyone with any input would be a great help đ
<@&286206848099549185>
@cinder violet Has your question been resolved?
<@&286206848099549185>
<@&286206848099549185> anyone any input or start for this ?
Even a way to start after differentiating ?
This issue im having is that once I multiply back the coefficients back in I get the same powers of X thus not needing to change the index to get a match leaving all A_n the same
Thank you for the resource
@rough storm is there anything I should be doing with the factional power at X^n+1/3?
Can you show your work so far?
This was from earlier, see how my X^n+1/3 are common, but also i have no need to change any index's
based on general solution from Frobenius as X=0 is a regular singular point
@rough storm its really from here im stuck as im not sure what is the best way to approach setting coefficients to 0 as A_n is common and so is the X^n+1/3
It may be a mess up in my indexing but im not sure
why are you adding a power of a 1/3?
Due to us wanting the series solution around X=0 and X=0 being a regular singular point we use Frobeniusâ Method
the lower case sigmas here are part of the indicial equation to find which will be the general solution for us to use
as sigma 1 -sigma 2 is not an elemet of Z we can use that case
@rough storm From here
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this is a calc class right? how do you find a tangent line?
@tawny vessel Has your question been resolved?
yeah its calc
well you find derivative and then find the line
okay, did you do that
but p is not even on the graph so idk
you want a line that satisfies two properties:
a) is tangent to f
b) goes through that point
you need to find all lines tangent to f, then solve for the y intercept using that point
sorry i don't get what you mean can't p go fit on multiple tangent lines of the graph?
ok so first i would find the derivative
and then i just have no idea what to do
okay, whats the derivative
(3/(x+1^2))
and now i have no idea what to do lol
your derivative is written wrong
so how you have a line with slope $\frac3{(k+1)^2}$ that goes through some point $(k, \frac{3}{k+1})$
are you familiar with point slope form?
I think yeah
if not, you should look it up, but you get
$y - (\frac{-3}{k+1}) = \frac3{(k+1)^2}(x-k)$
and you want it to go through the point (x,y) = (-2, 8/3)
you should be able to solve all solutions of k from this
and remember that this k is the x value of where the line intersects the original function
from that you should be able to find the lines easily
this seems to not have real solutions 
huh
oh i forgot a negative somewhere i think
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â
okay this should have two normal solutions, but I'm missing my own mistake somewhere
btw im looking at what you said earlier im trying to understand it
ok this makes sense to me since it has to pass through that line since its the tangent
hmm I dont know what went wrong here, all the steps seem correct
i dont understand what you mean by this
im using k as a variable that means (x at a point)
like im using k as the x of the original function
but regardless my point slope form has no solutions when you plug in the x and y, which is wrong
huh i see
Yeah okay I got this
yeah
okay great
so now we plug in our (x,y) into the point slope form to solve for k
you can verify this by hand, but you get $k = -\frac52,-\frac74$
now just plug your two different k's into point slope form and you get your two lines!
(the more roundabout way to do this is using point intercept form where you use k as x in mx+b and solve for b using the (x,y) point of the original function, but this is not needed)
heres the fact checking for the -5/2 solution
obviously you would simplify the green equation to not be a monstrosity, but it is the correct line
purple too, just for fun
I gotta step away for a sec, ping me if you have followup questions or dont understand something
@fleet condor Thanks
So what we did is we first found the derivative
Then we used the derivative in point slope form and then chose a point to find all the possible different slopes that would result in lines passing through that point
Then we solved to find which k values would result in it and then replugged into the derivative to find the slope, and then we solve for b and find the line?
note that in the point slope form we both used the derivative and a generic point on the original function
<@&268886789983436800>
the last step can also be simplified down to "we solved for k with the point given, then we plugged it back in to find the general form"
sharing that calc because im closing it and wont feel like typing it out again
@tawny vessel Has your question been resolved?
@fleet condor Thank you I understand most of it I just have a question about the point slope formula itself doesn't the point slope form only consider the slope and not the value of y when x is 0
Im not sure what this means
the point slope formula in general is just $y-y_0 = m(x-x_0)$, where (x, y) and (x_0, y_0) are points
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10cm paper is equal to how many m^2 of paper?
how many cm in a meter?
ik its .1 m so would m^2 be .01?
yep đ
ok thx
If it was 10 cm to begin with, then it'd be 10/100 = 1/10, which squared is 1/100, right?
Oh my bad. I thought he was answering your question
no worries!
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is there any textbook where i can learn about lines, planes and distances in 3D?
like distance between line and point in 3D, distance between plane and point, planes, lines, skew lines etc
its geometry
but is there any book on it??
where do i look in there @plucky elk
Just ask the same question
you can search or ask
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so say i have 3 parametric equations
for x y z
this is for a line in 3 space
now say i have a point (a,b,c)
how do i find the distance between the point (a,b,c) and my parametric equations?
so for example say my parametric equations are
x = -1+ 4t, y = -2+7t, z = -0.5-5t
how do i find the distance between (a,b,c) (whatever it may be) and these parametric equations
do i remove the Ts from the equation, and then find the equatio n ax + by + cz = 0??
what should i do
The distance from a point to a line has a known formula
Derivative
but i have a parametric equation with x,y,z
Do you know distance between two points?
no
Treat each x,y,z equation as a point
yes
There's a known formula for this too
so i find the distance between each point
i treat the parametric equation as a point
Yes
"the distance" is just the minimum along the line
so i have point a,b,c
Start with the distance from (x,y,z) to (a,b,c). It's a known formula
Begins like this
ok
You fill in the rest
That gives you an answer in terms of t yes
derivative?
Right

Probably a known way yes
yeah. the calculus way is probably better. but since there are parametric equations in linear algebra, say i have 3 points a(1,0,2) b(3,1,0) and c(2,2,2). Find the distance between point a and the line passing through b and c
so here what i would do is find the parametric equation of b and c
so i find vector BC
then i do the parametric equation stuff
so after i have my 3 parametric equations, i do what we did before (distance formula then find the derivative)
but, this is the calculus way
how do i approach this problem the linear algebra way
cuz i dont think my teacher wants me to find dervatives in a linear class hahah
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for question d
this is the question
i shouldve gotten -30 in decimal but instead if i convert that binary number ill get -62
where did i calculate it wrongly
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Why canât logs have negative bases? It should work out theoretically for example
(-2)^3 = -8
log-2 -8 = 3
Well what about $\log_{-2}(-7)$?
A Lonely Bean
It is even a real number 
Exponentiating with negative base can get really messy
So it's conventional to stick to positive bases
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Does anyone have any values that help me with this equation: a^2-b^2 = sqrt c
but c is a whole number
=>(a-b)(a+b) = c
(= sqrt c)
Does the question say anything about the values of a and b ?
tbh i dont think i phrased it right lol
let me just use examples
so the problem has this equation: x^2 + 8^2 = 17^2, x = 15
when they square the value it turns out to be a whole number
but im looking for a number combination that gives me a whole number as well
cause i did x^2+8^2 = 12^2 and got x = sqrt 63
you did the subtraction wrong, also x wouldnt be a real number
oh yeah i just realized but why wouldnt x be a real number
sorry i mean x would be a whole number
oh i know that i was trying to find values of b and c that gave me a whole number for x
but luckily i found some !
x^2 + 5^2 = 13^2
i just needed it cause my teacher wanted us to make word problems that related to triangles
like this
Sorry for any confusion
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(p -> q) -> (q V (not)p)
Can we say that this is the same as (p V (not)p) given that we can cancel out the -> qâs
I know both of then are tautologies
But still can we claim that they are the same expression
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Justine is paid $10 an hour for x hours. During a particular week, she earns $180.
Write an equation involving x to describe hours worked in a week to earn $180 and solve the equation by
inspection to find the value of x. (3 marks)
!status
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
so if she earn $10/h, how much would she earn working 1 hour?
$10
and 2 hours?
20
what did you do to get those answers?
so 18 hours
so if she earn $10/h, how much would she earn working x hours?
10x
yes
and now set that equal to 180
since thats how much she ends up earning in the problem
so 10x=180
yep, so there's your equation, what next?
so x=18? right
that's it and don't forget to include units with your answer, 18 hours
ok also can i say another question
sure
so if you multiply both sides by 3 you end up with what...?
2x+1 = 3 is not quite right, you completely forgot to multiply one side of the equation by 3
3 by 3?
$$3=\frac{2x+1}{3}$$
$$3(3) = 3\frac{2x+1}{3}$$
$$9 = 2x+1$$
Soosh
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what happens after u sub z in
and why do u sub e^itheta wouldn't u be subbing in the euler's formula of sintheta
do u convert it into cis??
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what is the difference between plotting and graphing
and thx if you have the answer
plotting means marking points
I wouldnt make a distinction between those two words
agree with Denascite, mostly they are used interchangeably but yeah when referring to drawing invididual points, you usually hear "plot the points" rather than graph the points. But you can also say "plot the graph of the parabola" just as well as "graph the parabola." so pretty much they can be used interchangeably but one might be used over the other more often for specific contexts
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thers a much simpler way to do it
when the power of the denominator is greater than the power of denimator
u just divide the top and bottom by the largest power of x
Is
nopt quite
what was ur final asnwer
i cant quite read it
0
right
u got it right
but two things
u need to specify if its coming fomr below or above the x axid
so in this case its $0^{-}$
Big Chicken




