#help-19
1 messages · Page 16 of 1
it is R-{1}
huh
yes
Im confused
exp : R -> R
exp(x) = e^x
yes?
exp(R) = R+
???
the image of the exponential function is the positives.
no.

it is non zero positives
yes sorry
,,\bR^+\coloneqq{x\in\bR : x > 0}
in french 0 is positive lol
this is the definition I am familiar with.
if you say positif, I wouldve understood
I'd advise restating your original question
so what you mean in symbols is clear.
,,\bR^+_0\coloneqq{x\in\bR : x \geq 0}
let f : R->R.
if f(R)=[0,+oo[, then f is not injective
yes
Right, ok, and its still false
then f not inj
Yes but its a hint
not N
You use precisely the same idea
Is what we're saying.
If you had to answer the same question for f: N -> N
and f(N) = {n + 1 : n in N}
how would you do this
thats the hint
You dont see this one?
that's still N
huh
{n + 1 : n in N} is definitely not N
thats the set without the 1st element of N
Im asking if you know how to construct an injective function from N into this set
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1037/375 (2056) +7*0
use google or a calculator
,calc 1037/375 (2056) +7*0
Result:
5685.5253333333
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hey, why do we have the two cases for 2x-1 here?
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There's a problem where you essentially have to solve the equation (10,000/x) + 500x = 2000 graphically, which is straight-forward and gives two answers, but I tried to convert the problem to 10,000 + 500x^2 =2000x and it has no solutions
!original
Please show the original problem, exactly as it was stated to you. A picture or screenshot is best.
If the original problem is not in English, then post it anyway! The additional context might still help helpers help you. Do your best to translate.
I do not believe that the original problem is neccessary here, what I am asking for is why you can't solve the equation $\frac{10 000}{x} + 500x = 2000$ by converting it to $ 10,000 + 500x^2 =2000x$
The intial equation gives the answers x = 0.59 and 3.48. The second one is unsolvable when using the quadratic formula
Seed
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From lambda = 1 we get [1, 2, 2]
Amazing
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how is the answer 0.8/c?,
i found the intersection, which should be (0.2/a+0.4/b+0.8/c+0/d)
so the lower bound should be 0 i guess?
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how can I solve this?
just plug in 2.0000000001
😎
kidding
first thing, the a can come outside of the limit
actually i think you do plug in 2.00000000000001
because its asking for only the right
which does exist and you can just plug that in
do u know if this is valid?
oh
should be x-2^2
at the top
and+x-2
but you dont need to combine the graction
just evaluate everything seperately
it is just asking you to plug in 2.00000000001 tho
but i end up with this
i am solving a bigger thing this is a part i need to use this method
then fine, lets combine the fractions
it should be infinity according to this graph
is what you get after combining the fractions
you didnt combine the fractions properly initially
what did i get wrong
here
if you're going to combine the fractions, you might as well also combine a
a=a/1
its not that its wrong, infinity-infinity is still infinity
just that you get a more clear answer
and what if the question didn't have 'a' then it would be infinity-infinity
ooh
ty for the help
yes
also suppsoed to be b-2^2
is this right?
i think the minus before the first fraction is what got me wrong
make a= a(x-2)^2/(x-2)^2
yes the same
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cosecx-8cosx = 0
0 < x < pi
!status
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3
what'd you do
that's sin2x=1/4
yh my bad typo
then i got my solutions of 0.13 pi and 2.89 pi
not sure if im right
or is second solution 2.35 pi?
i don't know how you got those, can you show your working out
i cant as im on desktop
im using radians
yh thats 0.13 pi
oh wait my calc might've been in deg lmao
relatable
,w 0.13pi
?
is it just 0.13 then?
and 1.4 is the other?
yes
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Stats.
I understand that $\beta = \frac{Cov(X,Y)}{Var(X)}$
AlexanderJ
Which can be rearranged like: $\beta = Var(X)^{-1}Cov(X,Y)$
AlexanderJ
And I can also find beta using a matrix equation:
$\beta = ({X}'X)^{-1}{X}'y$
AlexanderJ
Clearly, the $({X}'X)^{-1}$ in the matrix equation is analogous to the $Var(X)$ in the OLS equation, and the ${X}'y$ in the matrix equation is analogous to the $Cov(X,Y)$ in the OLS equation
AlexanderJ
But calculating the covariance and variance involves calculating the squared distances of observations from their means, whereas the matrix equation doesn't involve the means at all; it just uses the raw data.
And, I don't understand how we can do that. How does the matrix equation "work" if we're not really calculating the covariance between the independent x and dependent y variables, because we never calculate the means with which we could calculate variance and covariance?
I understand the derivation of the matrix formula, by differentiating ${e}'e$ and setting it to 0. Derivation isn't what I'm looking for. I'm looking for conceptual understanding.
AlexanderJ
@forest shale Has your question been resolved?
The same information is being used in the matrix formulation of OLS. It's just hidden by notation a little more.
You should make a small example X and y and calculate everything by hand from both definitions. You'll quickly see how they are equivalent
So, I've done, that, and I'm not seeing the equivalence. 😦
Did you get different answers?
Not at all. I just don't understand how ${X}'y$ in the matrix equation is analogous to the $Cov(X,Y)$ in the OLS equation.
AlexanderJ
For example, let's say I have a vector of x-inputs: [ 1, 2, 3, 5, 6 ], and a vector of y-outputs, [ 4, 3, 2, 1, 2 ].
So I can create a design matrix X: $\begin{pmatrix}
1 & 1\
1 & 2\
1 & 3\
1 & 5\
1 & 6
\end{pmatrix}$
AlexanderJ
So I can create a design matrix _X_: $\begin{pmatrix}
1 & 1\\
1 & 2\\
1 & 3\\
1 & 5\\
1 & 6
\end{pmatrix}$
```Compilation error:```! Missing $ inserted.
<inserted text>
$
l.57 So I can create a design matrix _
X_: $\begin{pmatrix}
I've inserted a begin-math/end-math symbol since I think
you left one out. Proceed, with fingers crossed.
LaTeX Font Info: Calculating math sizes for size <14> on input line 57.
LaTeX Font Info: Trying to load font information for U+msa on input line 57.```
And then when I calculate ${X}'y$ it returns $\begin{pmatrix}
12 \
33
\end{pmatrix}$
AlexanderJ
But I don't really see how that's analogous to the covariance of y and x, which I'd calculate thus:
$\bar{x} = \frac{1}{5}(1+2+3+5+6) = \frac{17}{5}$
$\bar{y} = \frac{1}{5}(4+3+2+1+2) = \frac{12}{5}$
Cov:$\frac{1}{5}((4 - \frac{12}{5})(1 - \frac{17}{5}) + (3 - \frac{12}{5})(2 - \frac{17}{5}) + (2 - \frac{12}{5})(3 - \frac{17}{5}) + (1 - \frac{12}{5})(5 - \frac{17}{5}) + (2 - \frac{12}{5})(6 - \frac{17}{5}))$
AlexanderJ
= –7.8
= –1.56
Edit: sorry, forgot to multiply by 1/5
So clearly you've made some assumption that doesn't hold
I don't really see how –1.56 is captured in the vector:
$\begin{pmatrix}
12 \
33
\end{pmatrix}$
OK, excited to hear where I've gone wrong
AlexanderJ
Xenophon
Will stare for 3 mins
I recognize straight away that the last vector there on the right-hand side is ${X}'y$
AlexanderJ
And I recognize that the middle element, the 2-by-2 matrix, on the right-hand side is ${X}'X$
AlexanderJ
Not quite
Uh oh
The inverse
Oh, I was trying to see that maybe the application of the 1/n*[complex sum] was the inverter
Ah, you mean because the formula for the inverse of a matrix is to flip the matrix like a mirrored transpose, turn the right diagonal negative, and then multiply the matrix by 1 over its determinant
Yes
Gotcha, that makes sense. I was wondering why n was on the bottom-right of that matrix for a moment
The point I'm trying to make is that if your calculation of $\beta$ is giving you a scalar, then you aren't even looking at the same thing as the matrix formulation.
Xenophon
You're just looking at the second element of the vector
Linear algebra is so slick that you sometimes forget how many details are being hidden behind the notation
I have had that problem before too
So, if I look at the matrix notation, is there a way to see how the Cov(x,y)/Var(x) is captured in the beta-vector's second element?
I'm asking because I really want an intuitive understanding of this, and I definitely have an intuitive understanding of the SLR case where the scalar beta is Cov(x,y)/Var (x).
Like, figuring out the covariance of x and y, then dividing the covariance by the S.D.s of x and y to "scale it" to the x and y variables, returning the correlation, then scaling the correlation by multiplying it by the S.D. of y divided by the S.D. of x...
...that makes intuitive sense to me.
All I'm doing is figuring out how one variable is far away from its mean in relation to how another variable is far away from its mean, and then doing some scaling a few times using the average distance from the mean (or that figure, squared) to give me a number that measures on average how one variable responds when another changes. I get that.
But when I look at the matrix notation, I'm really grasping for the intuition of how it captures that relationship!
OK, I have to go to bed. I hope that by the time I wake up, a magically intuitive explanation, or even just a hint of which direction to look in, will be here. Thank you in advance to anyone who adds something.
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can anyone give me a video that will help me solve this?
👉Learn how to solve a system (of equations) by elimination. A system of equations is a set of equations which are collectively satisfied by one solution of the variables. The elimination method of solving a system of equations involves making the coefficient of one of the variables to be equal in all the equations that make up the system, in ord...
how do I deal with the fraction
that's what I'm stuck on
A fraction works just the same
so make the denominator the same and cancel out?
I tired looking for a tutorial no luck
Yep.
I'll try ty
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Hi could someone help me solve this telescoping series. I'm writing out the partial sum but I think I'm making some silly mistake because the terms arent canceling out
Well first you can write that as 7/(2^(n+3))
Know that
write it as $\frac{7}{8 \cdot 2^n}$
nalin
could you explain how you get it to that form im not seeing it
$x^{a+b} = x^a \cdot x^b$
Stephen
2^3=8
Apply that to the 2^{n+3}
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proofs
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is
2i sqrt3
7
equal to
2sqrt3
------- i
7
A_CheeseFox
A_CheeseFox
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Idek where to start
try to move around the numbers to get y on its own
Alr
Y= -3/2+ 4?
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Was both the solution correct?
i cant answer the problem but i appreciate the cursive
Can you see the image@vapid quartz
Thanks
<@&286206848099549185>
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Hello, please help me with this task, I am using a translator so my answers cannot be quick.
use sine rule to find BD
then BCD and PCQ are similar triangles
so you can use ratio of BP/PC to find PQ from BD
Ok thanks
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@lilac acorn if you're doing induction, you are already assuming n is a positive integer
@lilac acorn your answer is basically done, you may take away stuff to meet your goal
you mean the things I wrote in the last step or..?
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Help idk how to do this
Show a picture of the full screen
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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'm told it's wrong
4. I got an answer and would like my work checked
5. I have a question about someone else's worked solution
6. None of the above
4
Im not sure if the answer is correct
So
F can not be a function of t if you are going to be using t as your "dummy variable" in the integral
Then it all looks correct
Id avoid the arrows though, it gets pretty messy and its hard to follow where youre going
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d
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Given linear regression y'=rx'. Prove that the r would be equivalent to the Correlation coefficient
why the slope of an linear regression would happen to be the correlation coefficient?
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help
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✅
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@wispy minnow Has your question been resolved?
<@&286206848099549185> no?
ok
A Note
at this point,
start with a
positive integers are 1,2,3,...
because d cannot be negative,
start with a = 2
$\frac{1}{d} = \frac{1}{2}-\frac{1}{b}-\frac{1}{c}$
and the smallest value that b can have
A Note
is 3
because 1/2 - 1/2 - 1/c is negative
so b = 3
$\frac{1}{d} = \frac{1}{6} - \frac{1}{c}$
A Note
and the smallest value that c can have
is 7
because when c<6, it's negative
when c = 6, it's dividing by zero
so
$\frac{1}{d} = \frac{1}{42}$
A Note
solving this equation,
d can have 42
the idea is to substract the biggest value possible that is smaller than 1 using $-\frac{1}{a}-\frac{1}{b}-\frac{1}{c}$
A Note
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help 😭
i think i know that its p^2 = 32 x q^2
bc all of the bases are x
dang it
you're not apply product law properly
is it p^2 = 32q^2?
yea…
which I said was wrong
p^2 = 32 + q^2
yes
that's not what you typed
oop i forgott he parenthesees
you could do that, but there's a more efficient method
pls tell
from
p^2 = 32 + q^2
subtract q^2 from both sides
then factor the difference of two squares
32 is a square..?
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How do I solve it using a calculator
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note it doesn't say what the exact shape of the box is
so just pick any shape (that is a rectangular prism aka a box) that gets you a surface area of 8m²
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if you increase the side length of a rectangle by double, what happens to its area?
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can someone help me with this
theres no given statement so i dont know how im suppose to do this
since its a reflection u know that angle 1 is congruent to angle 3
so would this be correct?
for the first line, since it's not really given, i guess you can write that a reflection bounces off a surface at the same angle as it hits it
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not sure what to do to get t * (n/3)
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and
what are the y coordinates of the points where y^3+x^3+30y^2=4x+3 has vertical tangent lines
diff questoin btw
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'm told it's wrong
4. I got an answer and would like my work checked
5. I have a question about someone else's worked solution
6. None of the above
you should not need conjugates, you get that limit by directly evaluating it.
However, you need to calculate the lateral limits (which will be different and thus the limit wont exist)
what are lateral limits
limits when you approach the value from a single side
lateral != vertical
okay
i'm answering first question, not second
how he's expected to do the second without knowing what a lateral limit is is beyond me
sorry just incompetent
@ivory mural Has your question been resolved?
everyone is conjugating and getting an answer somehow for the first one
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How come the answer isn’t C?
-3 and 1 arent the bounds of the region we are looking at
the region is [-2,5]
(c is in that region) [edit: for f]
But aren’t we finding inverse of f?
Oh wait
I think I understand
Is the answer A?
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Is this correct?
Yes
@sage bear Has your question been resolved?
.close
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So basically I need help on this basic geo logic problem where we need to make slogans into conditional statements, the statements are "I'm lovin it" by Mcdonalds, and "Like a good neighbor , Statefarm is there"
i need help making this into a conditional it doesnt flow well
If I exist, I am lovin it? Lol
would it be if I am eating mcdonalds?
it would be valid i guess
If I am eating mcdonalds, them I am loving the experience?
or would it be just "loving it""
because we have to do inverse
and contra positive so it sounds weird
If im lovin it, then im eating mcdonalds
is that fine or too vague
could replace 'it' with 'the food' or 'my meal' or something i guess
how about for the statefarm one
if im in need, like a good neighbor, statefarm is there
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Can I get some help on starting this
I am kinda stuck
Its an implication proof so $P\Rightarrow Q\equiv \neg P\lor Q$ right?
42
So its contradiction is the negation which is $P\land\neg Q$
42
What does it mean if f divides (m+n)?
$(n+m)\div f=c,c\in\mathbb{Z}$
42
42
Yes, but then what can you say about m/f since f doesn't divide m?
thats the contradiction?
$\frac{m}{f}=c,c\in\mathbb{Z}$
42
It's not divisible though
yeah
oh so $\frac{m}{f}\neq c,c\in\mathbb{Z}$
42
That's a weird way to write it. Maybe you can say that there is no integer such that m/f is an integer
Or there does not exist c in Z such that m/f = c
i dont think i can write that
i have to write it in a certain format and reason it
do i start my proof with f | (n+m)?
You can do either.
hmm
im confused, but i shouldnt be
so f|n means n = fc, where c is an int, and there is no int l that m = fl
so like fc + fl?
Hmm wait this presuposes that this l exists
Try and do (n+m) - n using this divisibility equivalent
That should do the trick
wdym
Like n+m = af and n = bf, so n+m - n = af - bf
lemme write this all down 1 sec sorry
It's alright
like this u mean?
and then do this
Well in this case what you wrote is just wrong. You should write n=fc and n+m = fd for some c and d in Z
oh wait am i trying to say that f | m proving a contradiction?
Yes
ok i was confused before
Once you do the subtraction and factor you'll see
alright lemme write it
So like this
And when i do (n+m) - n = fd - fc
there will be a contradiction?
and this step is substiting n in right?
Yes you substitute (n+m) and n in
ok lemme write this down
Here
I think thats done
just need to write explantion
Thank you so much, Idk why I was stuck for so long
Can you check this proof over for me? I think its all good, just wanted another opinion
It looks good
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Hello
$y=\frac{\frac{e^{x}-e^{-x}}{2}}{\frac{e^{x}+e^{-x}}{2}}$
LE SSERAFIM
How do I find the inverse of this
$x=\frac{\frac{e^{y}-e^{-y}}{2}}{\frac{e^{y}+e^{-y}}{2}}$
LE SSERAFIM
ewww
What do I do after this
well u can get rid of the 2 immediately
cancels out in the numerator and denominator
Oh yay
$x=\frac{e^{y}-e^{-y}}{e^{y}+e^{-y}}$
LE SSERAFIM
Yes
ok cool
Do I use ln now?
yea try it, see what happens
$\ln\left(x\right)=\frac{y+y}{y-y}$
LE SSERAFIM
Like this?
??
$\ln\left(x\right)=\ln\left(\frac{e^{y}-e^{-y}}{e^{y}-e^{-y}}\right)$
LE SSERAFIM
yep
now try some log properties
||if only i had a spare riemann around with a preamble filled with factoids||
???
lol that was a joke
use log properties
how could u separate that fraction into separate logs
I know riemann tho lol
oh lol
$\ln\left(x\right)=\ln\left(\frac{e^{y}-e^{-y}}{e^{y}+e^{-y}}\right)=\ln\left(\left(e^{y}-e^{-y}\right)\left(e^{y}+e^{-y}\right)^{-1}\right)$
LE SSERAFIM
I take -1 out?
Wait
No need actually
$\ln\left(x\right)=\ln\left(\frac{e^{y}-e^{-y}}{e^{y}+e^{-y}}\right)=\ln\left(e^{y}-e^{-y}\right)-\ln\left(e^{y}+e^{-y}\right)$
LE SSERAFIM
rewrite e^-y as a fraction, then make common denominators
then see what happens from there
$\ln\left(x\right)=\ln\left(\frac{e^{y}-e^{-y}}{e^{y}+e^{-y}}\right)=\ln\left(e^{y}-e^{-y}\right)-\ln\left(e^{y}+e^{-y}\right)=\ln\left(\frac{e^{2y}}{e^{y}}-\frac{1}{e^{y}}\right)-\ln\left(\frac{e^{2y}}{e^{y}}+\frac{1}{e^{y}}\right)$
LE SSERAFIM
Like this?
How?
$\ln\left(x\right)=\ln\left(\frac{e^{y}-e^{-y}}{e^{y}+e^{-y}}\right)=\ln\left(e^{y}-e^{-y}\right)-\ln\left(e^{y}+e^{-y}\right)=\ln\left(\frac{e^{2y}}{e^{y}}-\frac{1}{e^{y}}\right)-\ln\left(\frac{e^{2y}}{e^{y}}+\frac{1}{e^{y}}\right)=\ln\left(\frac{e^{2y}-1}{e^{y}}\right)-\ln\left(\frac{e^{2y}+1}{e^{y}}\right)=\ln\left(\frac{e^{2y}-1}{e^{2y}+1}\right)$
LE SSERAFIM
This?
What then?
use log division rule for each individual ln in the second to last step
lemme see if i can work a couple steps ahead to make sure im not leading u on a wild goosechase
Consider: $x=\frac{e^{2y}-1}{e^{2y}+1}\implies x(e^{2y}+1)=e^{2y}-1$
PajamaMamaLlama

another great emoji 
Thank you for da wae
u know how to go from ur last step to the answer?
ur last step in this is good
$$\ln\left(x\right)=\ln\left(\frac{e^{2y}-1}{e^{2y}+1}\right)$$
Remove ln
$$x\left(e^{2y}+1\right)=e^{2y}-1$$
LE SSERAFIM
$$x\left(e^{2y}+1\right)=e^{2y}-1$$
$$xe^{2y}+x=e^{2y}-1$$
$$xe^{2y}-e^{2y}=-1-x$$
$$e^{2y}=\frac{-1-x}{x-1}$$
LE SSERAFIM
ye
multiply top and bottom by -1 to make it less ugly
other than that u shd be good
$y=\frac{\ln\left(\frac{-1-x}{x-1}\right)}{2}$
LE SSERAFIM
Like this?
yea thats correct, the fraction just looks a little ugly
$y=\frac{\ln\left(-\frac{x+1}{x+1}\right)}{2}$
LE SSERAFIM
Like this?
Wait
Something wrong
$y=\frac{\ln\left(\frac{x+1}{-x+1}\right)}{2}$
LE SSERAFIM
Here
yep
and thats nice and correct and all
but to make it look amazing
id do
$y = \ln {\sqrt {\frac {x+1}{1-x}}}$
Stephen
Where did the root come from?
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Why do they use 1.645, shouldn’t it be a one tailed test since its only seeing whether they like the exam or not?
it's a confidence interval, not a z-test
O thanks
Just been a while since i did these questions and when i googled it it said u could have one tail
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uhh
no
why is what I did wrong
I just top minus bottom
keeping the square root on all of them
logs disspeared from the y and z
1/2Logx - (1 + 1/2y + 1/2z)
the first part is correct now right
and y and z are missing logs
but otherwise is good?
fu
you should be writing clear steps
Log10(10^1/2)
feels like you tried to skip ahead in your head
also unless you were told that x,y,z were positive, this messes up the domain
how??
1/2Logx - (1/2 + 1/2logy + 1/2logz)
whats wrong with this
the domain for that will be x,y,z > 0
whereas in the original, a pair of them could be negative
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Am I wrong?
i can totally read that
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3.a) proving by mathematical induction
I wouldn't set the "= 6p". It's not helpful to have p, which is a variable with no constraints
You're assuming 7^k - 1 is divisible by 6.
Prove 7^(k+1) - 1 is divisible by 6
Obvious step, pull the 7 out
It would be nice if we could pull something with a 6 out of that
7^(k+1) = 7(7^k)
Oh wow it’s crazy somehow I’ve never thought of doing that
I think I almost got it by using ‘p’ and ‘q’ but I don’t really get how you could do it without them
I’m very new to induction by the way
@sand hill Has your question been resolved?
I’m still not sure what to do
@sand hill
7^(k+1) - 1
= 7(7^k) - 1
= 6(7^k) + 7^k - 1
The first term is a multiple of 6. The other terms are divisible by 6 because of our inductive assumption
@sand hill Has your question been resolved?
Ah I see! Thanks for your help
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If I have this and square both sides, does it still keep the +-
Make the 20-x^2 in (a-b)^2 form
ahhh so then it just becomes a positive and the - of +- goes away?
I don't think they go away, I think you still have the +- there because (a-b)^2 = (b-a)^2
So you gotta take both into consideration
Hence the +-
Hmm. Maybe I'll need to give full context then.
I have a system:
A: y=sqrt x
B: y = +- sqrt (20-x^2)
After everything has been plugged in and solved, I'm supposed to have (4,2) as the solution but this +- part is confusing me.
Sqrt +-... or +- sqrt...?
As, I told you, when you convert '20-x^2' to (a-b)^2 form, the ^2 cancels out with the sqrt, so you have +-(a-b) = sqrt x
They did the +- part for you. I've sometimes been left to figure that out myself when I was given such problems
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this is an inefficient way to go about doing things. and i think you also messed up somewhere...
do you know de moivre's theorem?
...do you know the concepts of modulus and argument at least?
the angle a complex number makes with the positive real axis?
ok let's try doing it differently. do the words "cube root of unity" ring any bells to you?
well then
-1/2 + sqrt(3)i/2 is one of those
raising it to the 3rd power yields 1
which helps you a lot
esp. considering 2010 is divisible by 3
i would've said that it has modulus 1 and argument 120° but that'll be lost on you.
on a separate piece of paper work out its 2nd and then its 3rd power.
you're not doing what i told you, and also you've made a sign error on line 3
$-\frac{1}{2} + \frac{\sqrt{3}i}{2}$
Ann
this is what im asking you to raise to the third power
maybe work that out as $\frac{(-1 + \sqrt{3}i)^3}{8}$ unless you are a masochist
Ann
no, you dragged the full 2010 power along with it.
you can do calculations that are tangentially related to the problem and then tie them back to it later on.
maybe your teacher strictly forbids it
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$$\frac{1}{8}=\frac{1}{4c}$$
Lex1729
I know that c = 2, however why do I get c = 0.5 when I rearrange?
u dont get c = 4/8 , u get c = 8/4
Oh true, my bad
Also one more question
How do I integrate natural log functions like this?
$$\ln\left(3x+1\right)$$
Lex1729
integration by parts helps a lot
Is it possible to do it using u-substitution?
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Given a pyramid S.ABCD, base is a trapezoid, large side is AB. I, J, K are 3 points on SA, AB, BC respectively
Find find the intersection point of IK and (SBD)
Find the intersection of (IJK) with SD and SC
,rotate
So yeah I uh solved the first problem but now stuck on the 2nd one
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I need help with a)
I’ve honestly just forgotten how to work with permutations, combinations and factorials.
Not sure if what I have is right
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@sand hill Has your question been resolved?
@sand hill Has your question been resolved?
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ooh this is a conceptual question, although you can use tools from calculus to solve it
ummm it might help to draw a sketch of some function f(x) and mark points 0, a, and 2a
remember that integrals are area under the curve
$\int_0^{2a} f(x)$ $dx = \int_0^a f(x)$ $dx + \int_a^{2a} f(x)$ $dx$
nalin
like I said you can also use tools from calculus like combining and splitting integrals (as above), doing substitutions, and renaming variables
if you want to do it analytically, i would go through each of them and try to use those tools to rewrite the integrals into the original form, or argue why they're not equivalent
you could also define F(x) to be a notional antiderivative of f, and "evaluate" each integral
@mystic saffron Has your question been resolved?
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how do i solve for n
Multiply both sides by 4
same base firstly
why?
unhelpful.
Yeah that's kinda longer
write 1/4 as a power of 2
Start with the simple, rewrite 4 as a power of 2
ya just turn 1/4 to a base of 2
OR use the fact that $$\frac{1}{a} = a^{-1} $$ for $ a \neq 0$
Cyrenux
ok ya but its easier to turn 1/4 to power of 2
4 ^ -1
4^-1 sure but you need to recall your times tables and recognize 4 as 2 * 2
or 2^2
2^-2?
how do i make 4 ^ -1 into a power of 2
4^-1 = (2^2)^-1 = ?
how tho
no i mean how does it become 2 ^ -2
yea
ye
how
..
i get it now yea
alr
.close
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