#help-39
1 messages · Page 180 of 1
you didnt show how you got the orthogonal complement of T
nor the orthogonal complement of S
we can compute it together
let v =(x1,x2,x3,x4)
T = <(-1,1,0,0),(4,0,1,1)>
v . (-1,1,0,0) = 0
i) -x1+x2 = 0
ii) 4x1+x3+x4=0
i) -x1+x2 = 0 <==> x1 = x2
ii) 4x1+x3+x4=0 <==> x3 = -x4 -4x1
(x1,x2,x3,x4) = (x2,x2,-x4-4x2,x4)
T orthogonal is = <(1,1,-4,0),(0,0,-1,1)>
you prolly did a mistake when finding the orthogonal complement of T because the dimension of T orthogonal + T should give the whole space R^4
Hmm hold up
dim(T)+dim(T perp) = dim(R^4)
since T and T perp are complementary subspaces and both are subspaces of R^4 their dimensions should sum up to R^4
Also you didn't show how you got that basis for S
I like this approach more
yeah is using the standard dot product for a vector v = (x1,x2,x3,x4)
I mean we need to compute the orthogonal complements correctly
also is impossible W is dim 1 because it has nontrivial intersection with the orthogonal complement of S and the orthogonal complement of T
yeah now I need to find basis of S
when we have basis of S we can compute the orthogonal complement of S
i) 4x1 + x2 - x4 = 0
ii) x1 + x3 = 0
ii) x1 + x3 = 0 <==> x1 = -x3
Yes
i) 4x1 + x2 - x4 = 0 <==> x4 = 4x1+x2
x4 = 4x1 + x2 <==> x4 = -4x3 + x2
(x1,x2,x3,x4)=(-x3,x2,x3,-4x3 + x2)
S = <(-1,0,1,-4),(0,1,0,1)>
Perfect
let v = (x1,x2,x3,x4)
i) v . (-1,0,1,-4)=0
i) v . (-1,0,1,-4)=0 <==> -x1+x3-4x4=0
ii) v .(0,1,0,1)=0 <==> x2 + x4 = 0
I am trying to find orthogonal complement of S
And got it?
After having that it shouldn't be hard
-x1 + x3 -4x4 = 0 <==> x1 = x3 - 4x4
i) x1 = x3 - 4x4
ii) x4 = -x2
plugging ii) in i)
x1 = x3 + 4x2
(x1,x2,x3,x4)=(x3+4x2,x2,x3,-x2)
orthogonal complement of S is = <(1,0,1,0),(4,1,0,-1)>
Not -4?
I plugged ii) in i)
at first it was x1 = x3 -4x4
but then it became
x1 = x3 + 4x2
because ii) say that x4 = -x2
Yep
,, W \subset S + T \ W \ne S + T \ W \cap S^{\perp} \ne {0} \ W \cap T^{\perp} \ne {0}
xbz
this are the conditions subspace of R4, named W has to comply
So you're done?
well
We know W has at least one vector from the orthogonal complement of T and one vector at least from the orthogonal complement of S
and we know W is not a basis for S + T
but W is entirely contained in S + T
first let's find a basis of S + T
Okay
sorry I was in the toilet
ok good
And you don't need me anyway you're good
@stoic imp Has your question been resolved?
@stoic imp Has your question been resolved?
can anyone help me with calc 1
!occupied
Someone else is already using this help channel. If you need help with a question, please open your own help channel/thread (see #❓how-to-get-help for instructions).
@stoic imp Has your question been resolved?
@stoic imp Has your question been resolved?
what is that???
Its intersection of vector subspaces
S = <(-1,0,1,-4),(0,1,0,1)>
T = <(-1,1,0,0),(4,0,1,1)>
,w rref {{-1,1,0,0},{4,0,1,1},{-1,0,1,-4},{0,1,0,1}}
S+T=<(-1,1,0,0),(4,0,1,1),(-1,0,1,-4)>
T orthogonal = <(1,1,-4,0),(0,0,-1,1)>
orthogonal complement of S = <(1,0,1,0),(4,1,0,-1)>
,w rref {{1,1,-4,0},{0,0,-1,1},{1,0,1,0},{4,1,0,-1}}
,w rref {{-1,1,0,0},{4,0,1,1},{-1,0,1,-4},{0,1,0,1}}^T
,w rref {{1,1,-4,0},{0,0,-1,1},{1,0,1,0},{4,1,0,-1}}^T
,w rref {{4,1,0,-1,0},{1,0,1,0,0}}
i) x1 + x3 = 0
ii) x2 -4x3 -x4 = 0
x1 = -x3
x2 = 4x3+x4
(-x3,4x3+x4,x3,x4)
(-x3,4x3+x4,x3,x4)=x3(-1,4,1,0)+x4(0,1,0,1)
S = <(-1,4,1,0),(0,1,0,1)>
T = <(-1,1,0,0),(4,0,1,1)>
S + T = <(-1,4,1,0),(0,1,0,1),(-1,1,0,0)>
,w NullSpace[{{-1, 4, 1, 0}, {0, 1, 0, 1}}]
(x-4y, -y, x, y) = x(1,0,1,0) + y(-4,-1,0,1)
S n T = <(4,0,1,1)>
S perp = <(1,0,1,0),(-4,-1,0,1)>
S = <(-1,4,1,0),(0,1,0,1)>
T = <(-1,1,0,0),(4,0,1,1)>
,w Nullspace [{-1,1,0,0},{4,0,1,1}}]
(-x-y,-x-y,4x,4y) = x(-1,-1,4,0) + y (-1,-1,0,4)
T perp = <(-1,-1,4,0),(-1,-1,0,4)>
S n T = <(4,0,1,1)>
S perp = <(1,0,1,0),(-4,-1,0,1)>
S = <(-1,4,1,0),(0,1,0,1)>
T = <(-1,1,0,0),(4,0,1,1)>
S + T = <(-1,4,1,0),(0,1,0,1),(-1,1,0,0)>
,w rref {{-1,-1,4,0},{-1,-1,0,4},{1,0,1,0},{-4,-1,0,1}}
there is something off
Sperp n T perp I found it correctly
but when I try to look up the intersection between Sperp n Tperp with S+T the vectors are linearly independent
wtf man
there is something that I am missing
T perp = <(-1,-1,4,0),(-1,-1,0,4)>
S n T = <(4,0,1,1)>
S perp = <(1,0,1,0),(-4,-1,0,1)>
S = <(-1,4,1,0),(0,1,0,1)>
T = <(-1,1,0,0),(4,0,1,1)>
S + T = <(-1,4,1,0),(0,1,0,1),(-1,1,0,0)>
dim(S+T) = dim(S) + dim(T) - dim(SnT)
dim(S+T) = 2 + 2 - 1 = 3
,w rref {{-1,4,1,0},{0,1,0,1},{-1,1,0,0},{1,0,1,0},{-4,-1,0,1}}
(S + T) n S perp = <(-4,-1,0,1)>
,w rref {{-1,4,1,0},{0,1,0,1},{-1,1,0,0},{-1,-1,4,0},{-1,-1,0,4}}
T perp = <(-1,-1,4,0),(-1,-1,0,4)>
S n T = <(4,0,1,1)>
S perp = <(1,0,1,0),(-4,-1,0,1)>
S = <(-1,4,1,0),(0,1,0,1)>
T = <(-1,1,0,0),(4,0,1,1)>
S + T = <(-1,4,1,0),(0,1,0,1),(-1,1,0,0)>
a(-1,-1,4,0)+b(-1,-1,0,4) = c(-1,4,1,0)+d(0,1,0,1)+e(-1,1,0,0)
(-a-b,-a-b,4a,4b)=(-c-e,4c+d+e,c,d)
,, \begin{cases} -a-b=-c-e \ -a-b = 4c + d \ 4a = c \ 4b = d \end{cases} \ \begin{cases} -a-b + c + e=0 \ -a-b -4c - d = 0 \ 4a -c = 0 \ 4b -d = 0 \end{cases}
why is math so hard anyways?
,w rref {{-1,-1,1,0,1,0},{-1,-1,-4,-1,0,0},{4,0,-1,0,0,0},{0,4,0,-1,0,0}}
,, \begin{cases} a + \frac{5e}{32} = 0 \\ b - \frac{17e}{32} = 0 \\ c + \frac{5e}{8} = 0 \\ d - \frac{17e}{8} = 0 \end{cases}
why is math so hard anyways?
(a,b,c,d,e) = (-5e/32, 17e/32, -5e/8, 17e/8, e)
a(-1,-1,4,0)+b(-1,-1,0,4) = c(-1,4,1,0)+d(0,1,0,1)+e(-1,1,0,0)
e is free
we can choose e = 32
and then (a,b,c,d,e) = (-5, 17, -20, 68, 32)
-5(-1,-1,4,0) + 17(-1,-1,0,4)
(5,5,20,0)+(-17,-17,0,68)
(-12,-12,-20,68)
(-6,-6,-10,34)
(-3,-3,-5,17)
T perp = <(-1,-1,4,0),(-1,-1,0,4)>
S n T = <(4,0,1,1)>
S perp = <(1,0,1,0),(-4,-1,0,1)>
S = <(-1,4,1,0),(0,1,0,1)>
T = <(-1,1,0,0),(4,0,1,1)>
S + T = <(-1,4,1,0),(0,1,0,1),(-1,1,0,0)>
T perp = <(-1,-1,4,0),(-1,-1,0,4)>
S n T = <(4,0,1,1)>
S perp = <(1,0,1,0),(-4,-1,0,1)>
S = <(-1,4,1,0),(0,1,0,1)>
T = <(-1,1,0,0),(4,0,1,1)>
S + T = <(-1,4,1,0),(0,1,0,1),(-1,1,0,0)>
v = a(1,0,1,0) + b(-4,-1,0,1) , a generic vector of Sperp
v = (a-4b,-b,a,b)
a generic vector of S + T
(a-4b,-b,a,b) = c(-1,4,1,0)+d(0,1,0,1)+e(-1,1,0,0)
(a-4b,-b,a,b) = (-c-e,4c+d+e,c,d)
,, \begin{cases} a - 4b + c + e = 0 \ -b - 4c-d-e = 0 \ a -c = 0 \ b - d = 0 \end{cases}
why is math so hard anyways?
,w rref {{1,-4,1,0,1,0},{0,-1,-4,-1,-1,0},{1,0,-1,0,0,0},{0,1,0,-1,0,0}}
(a,b,c,d,e) = (-3/10 e, 1/10 e, -3/10 e, 1/10 e, e)
(a-4b,-b,a,b) = c(-1,4,1,0)+d(0,1,0,1)+e(-1,1,0,0)
a(1,0,1,0) + b(-4,-1,0,1) = c(-1,4,1,0) + d(0,1,0,1) + e(-1,1,0,0)
(-3/10).(e,0,e,0) + (1/10).(-4e,-e,0,e) = (-3/10).(-e,4e,e,0) + (1/10).(0,e,0,e) + e(-1,1,0,0)
(-3).(10e,0,10e,0) + (-40e,-10e,0,10e) = (-3).(-10e,40e,10e,0) + (0,10e,0,10e) + e(-1,1,0,0)
(-30e,0,-30e,0) + (-40e,-10e,0,10e) = (30e,-120e,-30e,0) + (0,10e,0,10e) + (-e,e,0,0)
e(-30,0,-30,0) + e(-40,-10,0,10) = e(30,-120,-30,0) + e(0,10,0,10) + e(-1,1,0,0)
e(-30-40,-10,-30,10) = e(30-1, -120 +10 + 1, -30, 10)
e(-70,-10,-30,10) = e(29, -109, -30, 10)
v = (-7, -1, -3, 1)
T perp = <(-1,-1,4,0),(-1,-1,0,4)>
S n T = <(4,0,1,1)>
S perp = <(1,0,1,0),(-4,-1,0,1)>
S = <(-1,4,1,0),(0,1,0,1)>
T = <(-1,1,0,0),(4,0,1,1)>
S + T = <(-1,4,1,0),(0,1,0,1),(-1,1,0,0)>
,w rref {{-7,-1,-3,1},{-1,4,1,0},{0,1,0,1},{-1,1,0,0}}
a(-1,-1,4,0) + b(-1,-1,0,4) = c(-1,4,1,0) + d(0,1,0,1) + e(-1,1,0,0)
,, \begin{cases} -a-b+c+e = 0 \ -a-b-4c-d-e = 0 \ 4a-c = 0 \ 4b -d = 0 \end{cases}
why is math so hard anyways?
,w rref {{-1,-1,1,0,1,0},{-1,-1,-4,-1,-1,0},{4,0,-1,0,0,0},{0,4,0,-1,0,0}}
i) a = -3/16 e
ii) b = 7/16 e
a(-1,-1,4,0) + b(-1,-1,0,4) = c(-1,4,1,0) + d(0,1,0,1) + e(-1,1,0,0)
a = -3
b = 7
-3(-1,-1,4,0) + 7(-1,-1,0,4)
(3,3,-12,0) + (-7,-7,0,28)
(-4,-4,-12,28)
(-2,-2,-6,14)
(1,1,3,-7)
T perp = <(-1,-1,4,0),(-1,-1,0,4)>
S n T = <(4,0,1,1)>
S perp = <(1,0,1,0),(-4,-1,0,1)>
S = <(-1,4,1,0),(0,1,0,1)>
T = <(-1,1,0,0),(4,0,1,1)>
S + T = <(-1,4,1,0),(0,1,0,1),(-1,1,0,0)>
,w rref {{-1,4,1,0},{0,1,0,1},{-1,1,0,0},{1,1,3,-7}}
W = <(1,1,3,-7),(-7,-1,-3,1)>
,, \textbf{Guys I have this subspaces: } \ \mathbb{T}^{\perp} = \langle (-1,-1,4,0), (-1,-1,0,4) \rangle \ \mathbb{S} \cap \mathbb{T} = \langle (4,0,1,1) \rangle \ \mathbb{S}^{\perp} = \langle (1,0,1,0), (-4,-1,0,1) \rangle \ \mathbb{S} = \langle (-1,4,1,0), (0,1,0,1) \rangle \ \mathbb{T} = \langle (-1,1,0,0), (4,0,1,1) \rangle \ \mathbb{S} + \mathbb{T} = \langle (-1,4,1,0), (0,1,0,1), (-1,1,0,0) \rangle \W \cap T^{\perp} \ne {0} \ W \cap S^{\perp} \ne {0} \ W \ne S + T \ W \subset S + T
why is math so hard anyways?
,, \textbf{Guys I have this subspaces: } \ \begin{align} \mathbb{T}^{\perp} &= \langle (-1,-1,4,0), (-1,-1,0,4) \rangle \ \mathbb{S} \cap \mathbb{T} &= \langle (4,0,1,1) \rangle \ \mathbb{S}^{\perp} &= \langle (1,0,1,0), (-4,-1,0,1) \rangle \ \mathbb{S} &= \langle (-1,4,1,0), (0,1,0,1) \rangle \ \mathbb{T} &= \langle (-1,1,0,0), (4,0,1,1) \rangle \ \mathbb{S} + \mathbb{T} &= \langle (-1,4,1,0), (0,1,0,1), (-1,1,0,0) \rangle \ \mathbb{W} &= \langle (1,1,3,-7), (-7,-1,-3,1) \rangle \end{align} \ \textbf{How do I prove the following conditions hold? } \ \begin{align} \mathbb{W} \cap \mathbb{T}^{\perp} &\ne {0} \ \mathbb{W} \cap \mathbb{S}^{\perp} &\ne {0} \ \mathbb{W} &\ne \mathbb{S} + \mathbb{T} \ \mathbb{W} &\subset \mathbb{S} + \mathbb{T} \end{align}
why is math so hard anyways?
.close
Closed by @stoic imp
Use .reopen if this was a mistake.
.reopen
✅
,, \textbf{Guys I have this subspaces: } \ \begin{align} \mathbb{T}^{\perp} &= \langle (-1,-1,4,0), (-1,-1,0,4) \rangle \ \mathbb{S} \cap \mathbb{T} &= \langle (4,0,1,1) \rangle \ \mathbb{S}^{\perp} &= \langle (1,0,1,0), (-4,-1,0,1) \rangle \ \mathbb{S} &= \langle (-1,4,1,0), (0,1,0,1) \rangle \ \mathbb{T} &= \langle (-1,1,0,0), (4,0,1,1) \rangle \ \mathbb{S} + \mathbb{T} &= \langle (-1,4,1,0), (0,1,0,1), (-1,1,0,0) \rangle \ \mathbb{W} &= \langle (1,1,3,-7), (-7,-1,-3,1) \rangle \end{align} \ \textbf{How do I prove the following conditions hold? } \ \begin{align} \mathbb{W} \cap \mathbb{T}^{\perp} &\ne {0} \ \mathbb{W} \cap \mathbb{S}^{\perp} &\ne {0} \ \mathbb{W} &\ne \mathbb{S} + \mathbb{T} \ \mathbb{W} &\subset \mathbb{S} + \mathbb{T} \end{align}
why is math so hard anyways?
I feel like I've seen this question being asked a month ago
ask in #latex-help next time
but you can look it up in detexify
Oops
my question
?
I was thinking of multiplying the vectors from S = <(-1,4,1,0),(0,1,0,1)> with
let v = (x1,x2,x3,x4)
for example like this:
i) v . (-1,4,1,0) = 0 ==> -x1 + 4x2 + x3 = 0
ii) v . (0,1,0,1) = 0 ==> x2 + x4 = 0
and then, seeing if the vectors from W = <(1,1,3,-7), (-7,-1,-3,1)> satisfy the equations i) and ii) , if one of the vectors satisfy the equations i) or ii) that would mean W = <w1,w2> either w1 or w2 is contained in S perp
for example if you evaluate w2 = (-7,-1,-3,1) in equation i) and ii) you get
i) 7 -4 -3 = 0 ==> 0 = 0
ii) -1 + 1 = 0 ==> 0 = 0
so w2 intersects with the orthogonal compĺement of S
we can do the same for the vectors from T,
iii) v . (-1,1,0,0) =0 ==> -x1+x2 = 0
iv) v . (4,0,1,1) = 0 ==> 4x1 + x3 + x4 = 0
,, \textbf{Guys I have this subspaces: } \ \begin{align} \mathbb{T}^{\perp} &= \langle (-1,-1,4,0), (-1,-1,0,4) \rangle \ \mathbb{S} \cap \mathbb{T} &= \langle (4,0,1,1) \rangle \ \mathbb{S}^{\perp} &= \langle (1,0,1,0), (-4,-1,0,1) \rangle \ \mathbb{S} &= \langle (-1,4,1,0), (0,1,0,1) \rangle \ \mathbb{T} &= \langle (-1,1,0,0), (4,0,1,1) \rangle \ \mathbb{S} + \mathbb{T} &= \langle (-1,4,1,0), (0,1,0,1), (-1,1,0,0) \rangle \ \mathbb{S}^{\perp} \cap \mathbb{T}^{\perp} &= \langle (4,1,0,-1) \rangle \ \mathbb{W} &= \langle (1,1,3,-7), (-7,-1,-3,1) \rangle \end{align} \ \textbf{How do I prove the following conditions hold? } \ \begin{align} \mathbb{W} \cap \mathbb{T}^{\perp} &\ne {0} \ \mathbb{W} \cap \mathbb{S}^{\perp} &\ne {0} \ \mathbb{W} &\ne \mathbb{S} + \mathbb{T} \ \mathbb{W} &\subset \mathbb{S} + \mathbb{T} \end{align}
why is math so hard anyways?
,w det {{1,1,3,-7},{-7,-1,-3,1},{-1,-1,4,0},{-1,-1,0,4}}
,w det {{1,1,3,-7},{-7,-1,-3,1},{1,0,1,0},{-4,-1,0,1}}
,w det {{1,1,3,-7},{-1,4,1,0},{0,1,0,1},{-1,1,0,0}}
,w det {{-7,-1,-3,1},{-1,4,1,0},{0,1,0,1},{-1,1,0,0}}
dim(W)=2
dim(S+T)=dim(S)+dim(T)-dim(SnT)
dim(S+T)=2+2-1=3
dim(W) < dim(S+T)
2 < 3
,, 2 \ne 3
why is math so hard anyways?
Closed by @stoic imp
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
x | 5 | 8 | 10 | 20
y | 6.4 | 4 | 3.2 | 1.6
inverse direct or neither
@forest gull Has your question been resolved?
Closed by @forest gull
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
I just would like to know if my approach here is valid
Tried my best to recreate it as good as possible in paint lol
@torn sky Has your question been resolved?
@torn sky Has your question been resolved?
Should I rephrase?
ye it is valid
you have to plug it back in and verify that it works though
Ah alright, thanks for the clarification
because in general, you may get extraneous solutions
like technically you would also get x=-10 but plugging it in doesnt give a valid equation
I've noticed with some of the other tasks indeed, where I got that x = -1, but that would work of course if log10(-1)
Yeah exactly, alright
On another note maybe
If we have 2lg(x)-5lg(x)+6 = 0
Generally with equations, if we substract or add we add to the whole number so we could substract 6 from each side to get 2lg(x)-5lg(x) = -6, but with multiply/divide/root/powers, we have to do that to each term, correct?
I'm not sure why I suddenly got that error in my brain, but it suddenly didn't make sense that I substracted only 6 from 1 term
you are always doing your operation to do the whole expression on each side
and with addition and subtracting, that is equivalent to just doing it to a single thing from each side
Okay, so what I said is valid as we would essentially just add or subtract 6 from the final number?
Whereas those other operations do something with 1 value, thus we have to do with with each term
whenever you have an equation of the form [expression1] = [expression2], always imagine performing an operation on the whole expressions
and then from there you decide whether you use associativity or distributivity
what do you mean subtract rom the final number?
So lets say we have what I said earlier, 2lg(x)-5lg(x)+6 = 0, we could in theory subtract or add 6 on both sides, which would just add or remove a 6 from the end product, in this case it makes sense to subtract 6, but if we were to multiply both sides with 2 we would do that with each term, like 2(2lg(x)-5lg(x)+6) = 2*0, where as add or subtract basically adds a new term
I hope that explains a bit what I got confused with?
yeah you can think of it that way
Closed by @torn sky
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
What did I do wrong ? Find area And perimeter
area of the circle and rectangle is wrong
you also didn't add it right for the perimeter
the individual parts seems right though
you didn't divide by 2 there
How?
It’s 17,13
M
Ok got it right
yup, should be that
Closed by @graceful spruce
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Can anyone tell me all measurements?
Meter
Hekto
Centi
etc.?
just google
Why when converting cm^2 to m^2 you have to divide by 100 and 100?
@urban sun what’s corner line?
In a square, the corner line is 15 cm find the area
Because 1 cm = 1/100 m
What is the corner line?
But why dtwice?
Idk… I’m asking you
Because you're squaring them !
It's not magic
do you know what ^2 means
It's just directly said
cm x cm
I think corner line is the yellow line
1m^2 = 1m * 1m = 100cm * 100cm = 10^4 cm^2
1cm^2 = (1/10^4)m^2
Stop with the attitude, I’m not your friend.
you're literally asking elementary problems
im convinced you are a troll
Then don’t talk to me.
ye
Ok
Closed by @graceful spruce
Use .reopen if this was a mistake.
You failed all subjects.
Quiet it down, Timmy.
Yeah right your grade is 1.
Lol
You’re so funny
You can’t even calculate it
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Please don't occupy multiple help channels.
.close
Closed by @graceful spruce
Use .reopen if this was a mistake.
You’re gonna fail at your life.
<@&268886789983436800>
This dude is real enemy of everyone’s enemy.
Bro wha going on?
Your whole personality is the definition of rude.
both of you shut up
perhaps you'll take a class at uni that teaches you how to be nice
when you do, you can come back here
<@&268886789983436800> i saw what happened why has andrzej not been banned too
Stop going on alt.
How is this not bannable huh
Because I was attacked first.
was less egregious and he wasn't the aggressor
Im allowed to defend myself.
having said that you should just call mods
I don’t want to disturb you.
He attacked other ppl
For helping him
How does that make sense
W moderation
i'm already disturbed. just call mods in the future
Ur just gonna allow this guy to have a false sense of authority over people helping him
He told some fella to chop chop
And to shut the fuck up and calling ppl worm
And thats allowed
Nice
ngl, andrzej pasts msg is a bit rude lmao
Also this, why did you attack Meolve like that??
Thats what im saying
yes, i was looking into those and was going to talk to him in private about that but yall have forced my hand
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Then i get banned for backing my fellow mathematicians against an absolute master of evil
How does this relate to maths STAY ON TOPIC id:customize
@mild berry Also stop being invested in this, it’s not concerning you.
Not at all. It's your (incorrect) interpretation
It concerns me i see serious failure of moderation and egregious behaviour
ugh. @graceful spruce yes your behaviour today has been very rude. please remember that helpers are volunteers. the main reason i'm not currently banning you is because this seems to be your first day here and you can learn
i see you editing posts btw
the fact that he is new implies that he is most likely a troll
He joined months ago
Thank you, otherwise there’s a mod here that would definitely ban me.
Is blud tripping
??
💀
Nice edit bro
Sure buddy, I need math help, but yall started to act in my channels.
Even he agrees he should be banned
No, im saying I’ve seen people getting banned for sending a sticker in #discussion
however, i think you can take a break from here for a bit. stay on topic in help channels. i'm closing this. don't talk about this anymore. if you encounter rudeness don't fight back just call mods. is2g
Or sending a meme video in a help channel.
i jsut saw this channel and just went to ur pasts msg and just think its a bit dumb that 2 ppl got banned and not him
.close
Closed by @unborn abyss
Use .reopen if this was a mistake.
I’ll, also keep an eye of these alts.
i'm also muting you for a few hours fwiw. please come back when you can be nice.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
prove If $\sup(A) < \sup(B)$, show their exists an element $b \in B$, that is an upper bound for $A$
ƒ(Why am. I here)=I don't Know
By definition $sup(A)$ satisfies the two following conditions: It' s an upper bound of $A$, and if any other upper bound exists , it's greater than $\sup(A)$.$\sup(B)$, too, must be an upper bound of $B$, and if any other upper bound exists , it must be greater than $\sup(B)$.
\
Let such an upper bound in $B$ not exist. Thus if there's no element in $B$ satisfying $\sup(A) \leq b$, it must be that $sup(A) > b ; \forall b \in B$. Thus $sup(A) \geq sup(B)$, which contradicts the given condition. Thus our assumption must be wrong, and such an upper bound in $B$ exists
ƒ(Why am. I here)=I don't Know
@sharp smelt Has your question been resolved?
<@&286206848099549185>
yeah that works. you can also take (sup (A) + sup(B))/2 which will be in between sup A and sup B. since it is smaller than sup B there is an element of B say b that is greater than or equal to (sup (A) + sup(B))/2 , so it is an upper bound for A
should be
Closed by @sharp smelt
Use .reopen if this was a mistake.
.reopen
✅
I have to show this isn'ttrue if $sup(A) \leq sup(B)$
ƒ(Why am. I here)=I don't Know
I was thinking $A=[0,1]; B=(0,1)$
ƒ(Why am. I here)=I don't Know
Well here sup(A) = sup(B) = 1 no ?
ywah, but there's mo element in b, that's an upper bound for A
Ah you was checking what happen when <= ?
yes
Interesting
That was the next subquestion
Ok ok then great counterexample
Which
Works with any x,y since you set A = [x,y] and B = (x,y)
y > x
And non empty
I believe
A=B=(0,1) also works
Can I close this channel now
Hi
Closed by @sharp smelt
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Im so confused.. i know it seems easy but im struggling 😭
Ive tried stuff 😭
what's the slope of 3x+y=-7
I have absolutely no idea
also what r the options on the right
Its just for a math lib
what's the slope of y = 2x
what's y(1)
Would it just be 2?
yes
y = 3x?
3?
i mean when x=1 what's y
Ohh
it's still 3 the +2 doesn't matter
Oh
cuz if u shift it up and down it's the same slope
+2 is just shifting up by 2 units
Ohh
m
Im so bad at this im sorry
we did m=2 and m=3 before
can u write this in that form
@old oriole Has your question been resolved?
Closed due to timeout
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
what?
picture on the way?
let x be the original price
17% were discounted and now it's 340
so $x-0.17x = 340$
artemetra
Result:
28220
Result:
409.63855421687
artemetra
you are still supposed to divide by 83
not multiply
what?
how many percent what
210% of 3000?
ah
yes
yes
divide 52425 by 0.85
,calc 52425/0.85
Result:
61676.470588235
,calc 52425*1.25
Result:
65531.25
yeah no
it's this one
yes, except it's 0.75 in the end
so here we have x-0.25x = 52425
we get 0.75x = 52425
oh cool icelandic
indeed
yep
well 52.425 isn't 25% of the original price, it's 100%-25% = 75% of the original price
this is why you use 75
Result:
6.9230769230769e+5
,w 225000/0.325
yep
Closed by @grave knot
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
I’m so lost
do you know the length of the right side in this picture
It's 2x
Huh
4x - 2x
Cuz u got the 2x on the right and 4x on the left
Do a and then split the picture into 2
Like a square and a rectangle
Wdym
Do you know what area represents?
Yes
and what's the area of a rectangle?
Do you know how to find area of this?
Closed by @stone imp
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
What do you think?
What do you know about the hypotenuse of a right angle triangle compared to its other sides?
?
Answer my question
Closed by @coral isle
Use .reopen if this was a mistake.
Bruh
don't be rude to helpers. either way I'm assuming this is a mute evasion #help-20 message
same picture
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
$(z-1)(z-3)(z+5)(z+7)=297$ determine the sum of the roots of the equation
Bob Pancakebutter
@desert solar Has your question been resolved?
!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
How did you get this?
show said calculations?
$(z-1)(z-3)=z^2-3z-z+3=z^2-4z+3$
Bob Pancakebutter
Closed due to timeout
Use .reopen if this was a mistake.
.reopen
✅
$(z+5)(z+7)=z^2+7z+5z+35=z^2+12z+35$
Bob Pancakebutter
okay. And why did you split those?
$(z^2-4z+3)(z^2+12z+35)=297$
It may be a good idea to start factorising $297$
I put together
i believe that to be unneeded
BananabrainJoe
After some calculations you get here
nevermind it's not
Then apply Vieta's formulas and you are done !
you had a lot of faith on that considering 297 is 3*3*3*11
$$297=11\times3^{3}=(-9)(-3)(3)(1)=(1)(3)(9)(11)$$ then immediately $4$ and $-8$ are solutions
when i factored it, i saw that it was not
如月あやみ Kisaragi Ayami
BananabrainJoe
there's no real need to expand anything
BananabrainJoe
i gave up too quickly
This Is the final sol?
as you aren't required to find the individual roots, just the sum
Did I do well? @light helm
noting that z-1, z+7 and z-3,z+5 form pairs that are centered at $z+2$, just let $y=z+2$ and let the formula for difference of two squares take it from there
it's this simple
ayami do you claim there are only 2 zeros?
note that in vietas formula, sum of roots (for degree 2+) isn't dependent on the constant term
it does require you to expand to get the first and second terms tho
如月あやみ Kisaragi Ayami
e.g consider the sum of roots for
x^2 + 2x + 7 = 0
x^2 + 2x + 13 = 0
x^2 + 2x - 3 = 0
x^2 + 2x + 5 = 0
x^2 + 2x = 0
But I find correctly
BananabrainJoe
yes
BananabrainJoe
Isn't it correct to do the exercise like this?
you could, but I'm hinting at a trick that can do it much faster
I also think I've found another way
Noting that $z-1, z+7$ and $z-3,z+5$ form pairs that are centered at $z+2$ we let $t=z+2$ and thus $$(z-1)(z-3)(z+5)(z+7)=(t-3)(t-5)(t+3)(t+5)=(t^{2}-9)(t^{2}-25)$$\$$=t^{4}-34t^{2}-72=297$$\If you now move everything to the left hand side and factor like a piece-of-cake quadratic you get $$\Rightarrow(t^{2}-36)(t^{2}+2)=0\Rightarrow t={\pm 6,\pm\sqrt{2}i}$$. Plug this back into $t=z+2$ and all four zeroes appear right in front of your eyes like magic.
that the sum of roots of
(z-1)(z-3)(z+5)(z+7)=297
will be the same as
||(z-1)(z-3)(z+5)(z+7)=c||
||(z-1)(z-3)(z+5)(z+7)=0||
and the roots of that and subsequently their sum can be determined quite easily
z=-8,4,-2+i√2,-2+i√2?
You can do it like this too
basically my solution but you used a harder to see substitution
@light helm right?
-8 is the correct answer
you dont have to seek validation from a moderator every step of the process
The sol Is -8!!!!
Sorry
icic im just wondering why youre being pinged so much here lol
yes, the sum is -8,
but my point is that this exercise doesn't actually require you to expand everything and/or solve the original equation
And how is it done?
i've already mentioned above
This ?
yes
(z-1)(z-3)(z+5)(z+7) = 0
z = 1, z = 3, z = -5, z = -7
Their sum is -8
yes
sum of roots in
P(z) = 0
is -b/a
constant term doesn't affect that
oh yeah, since the zeroes are symmetrical about some C shifting the graph up and down doesn't affect their total sum
makes sense
Closed by @desert solar
Use .reopen if this was a mistake.
@light helm One last question, but how did you know if you could use viete if you didn't expand first?
you have a polynomial
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
Channel closed due to the original message being deleted.
If you did not intend to do this, please open a new help channel,
as this action is irreversible, and this channel may abruptly lock.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
The drawing shows a rectangle 𝐴𝐵𝐶𝐷, in which side 𝐵𝐶 is 4 cm long.
On the sides of the rectangle, points 𝐸 and 𝐹 are marked, and segments 𝐸𝐹 and 𝐹𝐶 are drawn so that two identical triangles 𝐸𝐴𝐹 and 𝐹𝐵𝐶 are created. In both triangles, angles of the same measure 𝛼 are marked. Segment 𝐴𝐸 is 3 cm long.
Calculate the area of rectangle 𝑨𝑩𝑪𝑫. Write down the calculation.
did you try using similar triangles to get an equation for the length of AF or FB
its impossible to do that if i dont have another side...
@plush bramble
<@&286206848099549185>
I said an equation not solve for
EAF and FBC are congruent to each other.
i know..
that's all the information you need
but like i need other sides?
what does EAF being congruent to FBC imply?
i know what it is
and you know those two triangles are congruent
but i need to know what x will be
WHAT am i finding?
i only have 2 sides that are the same
what is the x you're talking abt?
since EAF and FBC are congruent to each other, then EA = FB = 3 cm and AF and BC = 4 cm.
the triangles are congruent
so yes EA = FB
i forgot that i can rotate the triangle
so you know BC, you can find AF and BF and AB = AF + BF, then you'll have all the information you need to find the area of ABCD
that is for similar triangles
we are dealing with congruent ones
then what now?
and it should be EA/FB = AF/CB
refer back to this
and this
48 cm^2
as I've mentioned before, this is unnecessary since you are dealing with congruent triangles and not similar ones
so its EAF and FBC
since EAF and FBC are congruent to each other, you can find FB = EA = 3 cm and AF = BC = 4 cm.
so AF + FB = 7 cm = AB
since you have AB and BC now, you can find the area of ABCD = 28 cm²
yes those two are congruent to each other
Result:
1.3333333333333
Closed by @crimson bloom
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
What is the expected value for the number of siblings just by looking at this graph?
"The expected value is the mean of the possible values a random variable can take, weighted by the probability of those outcomes."
so sum up $\sum_s P_s * s$
Adum
but how would u do it without calculations
just by looking at the graph
would it be the average of 0 and 2 since they are the same
so approx 1
wherever the mean of the distribution falls basically, so yeah 1, but slightly to the right because of the extra 0.03
i see, ok
but also, if we were to use calculations, how would it work?
like how exactly do u do "greater than 3"
0(0.36) + 1(0.25) + 2(0.36) + 3(0.03) ... and then?
I would just estimate with 3*0.03 for the tail, but you cant get an exact answer without knowing the full distribution
i see, alright okok
thanks for ur help
.close
Closed by @river lodge
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
One message removed from a suspended account.
One message removed from a suspended account.
Kenzo
One message removed from a suspended account.
Missing dr or Delta r
One message removed from a suspended account.
Kenzo
One message removed from a suspended account.
@buoyant garnet Has your question been resolved?
One message removed from a suspended account.
You just need to calculate the two volumes and subtract them
Volume of sphere of radius a = (4π/3) * a^3
what riemann said
One message removed from a suspended account.
🤔
Kenzo
what
I don't know what "did" means
One message removed from a suspended account.
You have to explain your work
huh
One message removed from a suspended account.
lol
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
🤔
You're still not explaining where this comes from
brother are you even reading the same question
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
This is volume
$SA = 4\pi r^2$
knief
How did you get from volume to this
$r = a \to r = a +\Delta r$
One message removed from a suspended account.
knief
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
not the same question at all
One message removed from a suspended account.
they didn’t even take the derivative
just delta r = 1, since 13-12 =1
One message removed from a suspended account.
knief
One message removed from a suspended account.
🤔
One message removed from a suspended account.
and a sitting out there
One message removed from a suspended account.
you differentiated V for some reason
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
not yet
One message removed from a suspended account.
you don’t?
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
Kenzo
One message removed from a suspended account.
This should be a instead of 10 and Delta r instead of 0.05
Then expand and simplify
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
Wut
One message removed from a suspended account.
(a+b)^3 = (a^2 + 2ab+b^2) * (a+b)
Kenzo
Keep multiplying
One message removed from a suspended account.
Kenzo
One message removed from a suspended account.
One message removed from a suspended account.
Kenzo
One message removed from a suspended account.
One message removed from a suspended account.
Your last term is incorrect
One message removed from a suspended account.
Kenzo
One message removed from a suspended account.
Yea just cancel and you're done
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
Kenzo
One message removed from a suspended account.
(4/3)pi
One message removed from a suspended account.
One message removed from a suspended account.
from here, you could:
factor out (4/3) pi
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
i don't know i haven't read the question in detail
One message removed from a suspended account.
One message removed from a suspended account.
this doesn't mention the values of a and delta r
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
how does your book describe "linearization"?
One message removed from a suspended account.
One message removed from a suspended account.
i see this one but i don't understand
One message removed from a suspended account.
One message removed from a suspended account.
ah
One message removed from a suspended account.
but the derivative where? at a=10?
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
ah
i think i understand
you had taken the derivative of the volume earlier, right?
what did you get
One message removed from a suspended account.
This is just the linear Delta r approximation
One message removed from a suspended account.
yes
The higher order powers are close to zero
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
the process seems correct to me
One message removed from a suspended account.
One message removed from a suspended account.
in order to find the value of the derivative at a
wait
that's the answer to the first question
One message removed from a suspended account.
delta r is meant to be small, so whether you plug in a or a+delta r, it should yield approximately the same value for the derivative
One message removed from a suspended account.
One message removed from a suspended account.
in order to find the rise
the derivative is rise / run
so you multiply by the run, which is delta r
One message removed from a suspended account.
One message removed from a suspended account.
One message removed from a suspended account.
you're welcome
One message removed from a suspended account.
Closed by @buoyant garnet
Use .reopen if this was a mistake.
Send your question here to claim the channel.
Remember:
• Ask your math question in a clear, concise manner.
• Show your work, and if possible, explain where you are stuck.
• After 15 minutes, feel free to ping <@&286206848099549185>.
• Type the command .close to free the channel when you're done.
• Be polite and have a nice day!
Read #❓how-to-get-help for further information on how to ask a good question, and about conduct in the question channels.
I'm taking AP Calc and we were learning about related rates. I wanted to know if I'm on the right track? I have no clue what I'm doing lol
@knotty prism Has your question been resolved?
No it has not yet
How did you get r=h/5? math doesn't seem right there
Closed due to timeout
Use .reopen if this was a mistake.
.reopen
✅
Could u explain what steps I did wrong?
Well, when h is 20, r should be 5, right? If you say that r=h/5, then i simply ask you what is 20/5?
With that minor correction, you can now express V as a function of h. Then, to relate their rates, you differentiate both sides of your equation with respect to t
So for volume I got V=1/48(3.14)(h^3)
3.14 would be pi ofc
But im not sure what the nexts steps are, that's where I'm confused
if it makes you feel any better related rates is by far the hardest topic in that class
(Until you get to integral calculus then have fun)
Very very close
Oh heck no😭
h is a being considered a differentiatiable function of t. You can call it h(t). So for RHS, you need chain rule
Would it look like this?

You simply need to now solve for dh/dt
Could u explain this step please? I'm not sure what u mean
You have dh/dt as the only unknown in your last equation. It's just algebra now to solve for it
