#help-39
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Yeah
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@rose sentinel
Yo
Half of 144pi, which is the correct answer (right?) Would be the amount needed of EACH enamel coating, the white and the blue
So yeah I agree with you
Yes
Wait yeah
Yeah I see you just never multiplied it
Okay alright then so the book is wrong
5th time so far
Out of like 1.2 million so far
Thanks
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Is this correct?
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$\int t^2 \cos t dt \$
$u = t^2, v = \sin t, du = 2t dt, dv = \cos t dt \$
$ t^2 \cdot \sin t - \int \sin t dt \cdot 2t \$
$t^2 \sin t + 2 \cos t \frac{t^2}{2} + c \$
Tomi
bro explain what u did with the second integral? it literally just looks like u integrated both seperately?
im using the integration by parts formula
yeah obv
then what did I do wrong?
u cant just integrate sint * 2t dt like that
there are 2 functions of t being multiplied
can you stop spamming this shit?
?
then why are you annoying me?
this is my help thread, feel free to open a new one
so what would I use there, do the integration by parts again?
yes
so do it over the new integral which is sin t dt \cdot 2t
yes
You could also the chart rule thing
Useful when u have to do Integration by parts more than once
And faster
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how can you have some $\int f(x)\text{ dy}$?
nameless individual
i dont get it?
i changed the x to y
.
is it always like the variable - X or can it be x - variable
im kinda confused on the r
it can be anything
should be $x-2$
caspar
if you are rotating around x = 2
can you explain how to like get that
wait isnt it x + 1
no
?
@brave schooner?
let me do the problem and ill explain after, need some refreshing
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whats this equate to and why?
this is generalized union for big U, and cartesian product for <a,b>
Start with the Cartesian products
Usually I see index notation for unions like these but I guess it’s already naturally indexed the way it’s a set of two objects
@pulsar stump Has your question been resolved?
i am, what is it
Do you not have a definition from your notes or textbook?
basic one, im asking to check what it is
so what is it
So in general with your notation it’s defined as
<A,B> := { (a,b) : a in A and b in B }
You asked about the Cartesian product, the thing you sent now is for the union..
ik what cartesian product is
do you not see the union sign?
Uh yeah, I told you to start with the Cartesian products
theyre there and theres nothing to do with it
i just want an =... answer
Is it not better if I guide you towards the answer?
Also I’m guessing you missed curly brackets for 0 and 1 here?
actually thats how you write the cartesian product (0,{2, 3})
first element is in Natural numbers for example and the second element is a subset of Natural numbers
i.e $<a \in N,b \in P(N)>$
Ayanokoji (always ping me)
Alright so why write <> ? Your question implied it was a calculation to be done.
That’s just an ordered pair and not a Cartesian product
Unless your notation for ordered pair is <>
yes, 2 pairs from the cartesian product NxP(N)
it is a calculation, what is the set resulting
from this
it is, more obvious
() is a hell to use for everything
Okay good, that was not obvious from your message. Let’s move on
alright
So at the moment there’s another problem
You have a set of ordered pairs
Your Cartesian product gives a set of pairs, so something is missing here in order for you to take the union
what is?
So please show the original question.
im trying to build up to it
f(0)={2,3}
f(1)={4,5}
if you see where i went with this
but does it matter?
Yeah since we can’t take the union otherwise
If you just have a union of a set of pairs
You can’t do anything
teacher's definition
UF while F is what i drew
And in our case we didn’t
i see
But now we can
so what do i do here
Okay so what is A?
is the dom() A->P(B)?
a set, undefined further
same for B
some sort of set, no givens
also not neccasarily H is a function
thats a follow up
Are you sure this is the original question? If its undefined it’s best to leave the union as is
As you can’t really do anything
But maybe create a predicate of some kind with it
yeah 100%
My question is then, how did you get these numbers?
Or these?
i said A=N, B=N, and just took some numbers (small sample) to understand the union
purely to see what the result set will be
Is B the set of outputs for f?
no, P(B) is
And so B is arbitrary here too?
as defined here
yes
Okay let’s try with this one
So since there’s only two elements from A, 0 and 1
The union which is indexing through A will just be a union of two sets
yes keep going
but can you just write the =...
no
thats not true
Hm did I miss something?
,(0,{4,5}) is not defined as a singleton of a x f(a)
only <0, {2,3}> is where f(a)=f(0)={2,3}
Oh right, forgot f(1) was {4,3}
Ok let me rewrite it
Namely the union {<0,{2,3}>} U {<1,{4,5}>}
Do you agree?
yes
not it's just the union of them
nvm
i think i got the answer
the range is A->B
and dom is A->P(B)
Yeah and I think what we notice here is that this is just the same as the image f({0,1})
well idk about that
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@pulsar stump are you still there?
I missed a big error throughout this chat
Can you tell me what the Cartesian product {0}x{2,3} is?
yeah {<0,2>,<0,3>}
Yup, you wrote {<0,{2,3}>} earlier
And I somehow missed that
And didn’t correct it
So since you gave the correct answer i guess it was just a minor mistake right?
yeah no worries
ty again mate
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I need help with 5th iv)
@strange rose Has your question been resolved?
<@&286206848099549185>
How far have you come so far?
I took x=tan^-1 x and differentiated that after substituting
I just want to know what course you're doing
obv maths/calculus but like what level (e.g a level, AP, degree etc.)
have you tried u sub?
12th grade (highschool)
yeah didnt work
can you show your previous results?
pls bare with my hand writing
dang your curriculums wild
@strange rose Has your question been resolved?
Indian?
yeH
ye le
1/2 hona chahiye
you get the idea of keeping x as tan theta from 1+x^2 because of the identity
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hi
I hv my maths test tomorrow on Differentiation and Application of derivates
AOD has sums where we have to find rate of change of some shapes and etc
does anyone have any tips on how to go about these sums
I always mess up here although my concepts of Differentiation are strong
any tips?
<@&286206848099549185>
you mean related rates?
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Proof 0.999...998 = 1
x = 0.999...998
10x = 9.9.....98
9x = 9
x = 1
I randomly made up this proof. I just started Real Analysis and I learnt that two numbers are the same if you cannot find any number inbetween them. This would seemingly contradict the proof above because between 1 and 0.999...998 is 0.999...
What am I not understanding?
uhm
in which position is the "8"
if there's an infinite number of 9s
there is an ENDLESS supply of 9s
so there is no "end"
to put an 8 to
0.99…998 < 0.99…999 <1
Not sure this is true
idk either
ok so
Makes sense I suppose
if you put an 8
it means you have to put it after a FINITE amount of 9s
so
let's say 1000000 9s for example
and then an 8
that's possible
but you can't put an infinite amount of 9s
AND THEN put something else
because there is no "and then"
i don’t thing this is true tbh, it makes sense intuitively but we are just going by definitions that 0.99..98 => there is a finite amount of nines, why?
this is literally the definition of decimal expansion
a decimal expansion is a sequence of numbers
so the decimal expansion of pi looks like
first number : 1
second : 4
third : 1
then 5
then 9
etc...
you can put all those numbers in a sequence
so the REAL issue here is that 0.99...98 is not well defined when written like this
Uhh i think you would first have to define 0.99..8 properly
yws this
so
as long as you have a well defined sequence of digits 0 to 9
you can define the number with that decimal expansion
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why does $\overline{c}+d = c+d$
@midnight haven Has your question been resolved?
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is this correct?
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What do I do with the 3^-2/4^-2 and the 3^3/2^3 in this
faiyrose
Oh yeah I noticed that
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is there a way to simplify this first?
to shorten the process
and avoid the messy roots and fractions lol
cuz, like, i evaluated it one-by-one lol
Sum to product, I presume
also kind of looks like sum of cot
sum of cot?
oh
but sum to product is guaranteed to make progress i think, so probably worth doing that instead
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where's pi/2 and 3pi/2 coming from
Tanx = 0
It's wrong btw
I'm asking where I went wrong
I factored it
Got tanx = 0 and tanx = -1
Solved for that
you didn't solve tan(x) = 0 correctly
Idk where I went wrong
Oh it's sin/cos
M
Oops
Jeez I am rusty
Sorry I haven't done trig in years
Ok more like half a year but so
Still
Ohhjh
2pi and pi then
Ok I got 0, pi, 3pi/4, and 7pi/4
@light helm is that correct
@tame apex Has your question been resolved?
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My book asks me to decide if this is a vector space. Its definitely not given it doesn't pass the scalar multiplication closure rule
however i also dont think it passes the addition closure either.
here is the question:
decide whether or not this set is a vector space. The set of functions {f: R→ R | df/dx +2f =1}
It also doesn't contain the 0 element
As long as you can show it breaks one of the conditions, it isn't a vector space. You don't necessarily need to worry about the others
howso, wouldnt 0*(1/2+Ce^-2x) = 0?
oh wait would it need to be another vector
are you refering to 0vector + V = V
or the 0*V=0
I mean the zero vector, f(x)=0 does not satisfy that differential equation
But also what you said is true, it doesn't have closure under addition or scalar multiplication
wouldnt the zero vector be -1/2-Ce^-2x
gotcha
such that -1/2 +1/2 +-ce^-2x +ce^-2x = 0
no thats additive inverse
aah
The zero vector in a vector space is the additive identity, like (0,0,0) in R^3
For a set of functions like this, it's just the zero function f(x)=0, since adding that to another function g just gives g
right
Yeah but you only need to show that it breaks one of the conditions for a vector space
So if you showed that it doesn't have closure with scalar multiplication, then that's enough to prove it's not a vector space
gotcha, thank you!
Np 👍
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so what all do I have to prove here?
remember only if is a <=
doesn't even look like it should take more than a one-liner proof.
so I just prove this
no
I thought it was an iff statement
so will this suffice ?
yes, works
v1 ∈ V1 implies λv2 ∈ V2
... So what?
V_1 is a subset of V_2
there's an even simpler proof here
if V_1 is contained in V_2 then their union is just V_2
which is a subspace, done
yea the other direction is the harder part of course
if V1 and V2 are subspaces and V1 U V2 is a subspace, then either V1 is contained in V2 or vice versa
could I have another hint
yea, try a contradiction... it would go like this:
suppose V1 and V2 are subspaces and V1 U V2 is a subspace
suppose for a contradiction that neither is contained in the other
then there is some x in V1 but not in V2
and there is some y in V2 but not in V1
other than the common 0 element, right?
see if you an find a contradiction
there might be other stuff in common too, but suppose neither is completely contained in the other
so each one has at least some elements not in the other
probably need more detail/justification for why x+y is not in V1 and not in V2
why isnt x + y in V_1?
why can you conclude that?
(also i think the proof for this without contradiction is a bit cleaner)
y isn't in $V_1$
ƒ(Why am. I here)=I don't Know
so $x+y$ isn't defined
ƒ(Why am. I here)=I don't Know
right
you can definitely do x + y
can I have a hint in that case?
express y in terms of x and x+y
y = some expression using x and x+y
$y=x+y-x$
ƒ(Why am. I here)=I don't Know
yes
so if x + y was in V_1, then you'd have
,, y = \underbrace {x + y}{\in V_1} - \underbrace x{\in V_1}
the conclusion is?
y is in $\V_1$
ƒ(Why am. I here)=I don't Know
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but we know that not to be the case
so x + y \in V_1 is impossible
So I basically repeat something similar for $V_2$ and I'm done, right?
ƒ(Why am. I here)=I don't Know
yes
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how do i solve for (b)
if you mean 2
the odd terms can be written by a+(n-1)(2d)
n=1: a 1st term
n=2: a+2d 3rd term
n=3: a+4d 5th term
where n is the nth odd term
or do you mean 5b?
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A function of K^n->K^m with K being real or complex numbers is partially differenriable in all n coordinates at a given point. Is it necessarily always also continuous at that point?
Is the inverse statement also true? If not, what's a counterexample?
(I am assuming "yes" and "no" respectively, but that's mostly vague recollection that I think I remember hearing as a side note in some lecture)
id think that both are false
both are false
continuous does not imply differentiable obviously, and partial differential just means that the partial functions are continuous
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Can i please get some help with a)
Is this high level math?
this is stats
It is so hard
Its called statistics
<@&286206848099549185>
nope
nope
@winter leaf this is called stats, its basically where you learn about probability
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Could someone explain to me $p \rightarrow q$ the logic behind it?
Merineth
Afaik "if p then q" is the official meaning of it?
And it's only false if p = true nad q = false
Why is that the case? And is there a better way to remember it?
nel
I mean there are only 4 pairs of values to check
One way is think of a real life example
In real life, if the kettle is boiling, then there is water in the kettle
That's the thing it's for
Like for example if i were to rephase it as :
p: it rains
q: I bring an umbrella
This is a worse example
Hmm
We are given this on our formula sheet
ANd i can see that it's only false when p is true and q is false
I just mainly dont understand it?
especially the p = 0 and q = 1
If there is no water in the kettle, then it's boiling????
is true? xD
Taking @vestal tapir 's example
if the kettle is boiling, then there is water in the kettle
p = "the kettle is boiling"
q = "there is water inside"
The if-then statement is just a statement, it can be true or false
Why did you swap p and q?
No
huh
"if there is water inside the kettle then it's boiling"
That's not a true statement in the real world
You can have water inside the kettle and have it not boiling
If there is water in the kettle, then it's boiling
p q
so almost, the "if" is not part of p technically
Water in the kettle is the if and the statement that it's boiling is q?
so, if there is no water in the kettle and it's boiling, you can't disprove $p\implies q$
You're mixing everything up...
nameless individual
here's an OR statement "Josh went to the dentist or he's at home"
I don't know if A is true, I don't know if B is true, i know something worse, something less useful
that A + B > 0, arithmetically
like any OR statement it's equivalent to an implication
"if Josh isn;t home, he went to the dentist"
A → B means A <= B, "artihmetically"
if p then q \
$p \rightarrow q$ \
if there is water in the kettle, then it's boiling
Merineth
How is this wrong?
a kettle
or is it reversed?
this could be true for some situation
if it is boiling, then there is water in the kettle
but like, the other way around is more true
yes that one is always true
A being true is sufficient for B being true
B being true is necessary for A to be true
like, it's not an analogy
it's an actual implication, it's meant in the same way
so you're confused if you're trying to see how it applies to the topic, it's the topic
Hmm i sincerely dont understand to be honest
i'll just copy from the formula sheet instead of tryingg to learn it
the logic is that it's not just a binary operation, it's a statement that tells you something
that's what makes it confusing, that it's kinda both
b + c doesn't tell you anything, but A V B does
like when you see A V B in isolation it's usually to imply that A V B is true
@gilded hollowI actually want to figure this out, it's a common question and I never get what people mean, what are they missing
Honestly it got to complicated for me to understand
ok
So i just decided that it's fine not to understand it
I do have another question however revolving tautology
I feel like you keep doing that and it's going to bite you later
last attempt then
there are 16 different logic operations we can do on 2 variables, some are more useful, so you learn them
A → B is one of 16 operations, it's like saying A is less than or equal B, A <= B
Perhpaps, but i also tend to get stuck on something and sit on it for hours until i finally figure it out but by that time i'm to exhausted to continue studying
it's very useful, we have a thing for it in English
"if then", at least often, means A → B
just like we have and in English
Show that the summary is a tautology: \
$p \rightarrow (q \rightarrow p \land q)$
\land?
Merineth
I can formulate in words why this is a tautology
you probably just translate it to ORs
That's pretty easy to show by translating the "implies" into "not p or q"
Ooh okay so i am supposed to transoform them?
I assume so
Yes
Yeah, you can remove the parentheses
Merineth
$\neg(p \land q) \lor p \land q$
Merineth
Yes
Yeah you have (not r) or r
Yeah okay that makes a lot more sense
Seems way more plausible that i'm supposed to solve it by showing like that
instead of fomulating in words lol
Well yeah maths classes are going to ask you to use symbols, not words
I def need more practice
Prove that it's a contradiction : \
$(r \land \neg q) \land (p \rightarrow \neg r) \land ( \neg p \rightarrow q)$
Merineth
I have to leave but this is gonna be more of the same, get rid of the implications and use some de Morgan and whatever
Instead of rewriting it, can i write it using a truth table?
We can easily conclude that the only way for the statement to be true is when all the statements between the $\land$ has to be true
Merineth
So we find every possible outcome for the statements to be true
That works too, it's just more laborious
Yeah i realized that ;-;
very intensive thinking
I wouild like to do your method of simplifying it
but i'm having a hard time finding an appropriate formula
(r n ~q) n (p -> ~r) n (~p -> q)
r n ~q n (~p u ~r) n (p u ~q)
r n ~q n p n r n ~p n ~q
but p n ~p = 0
Hmm i cant seem to understand the second step
you removed the parentheses
but what about the second part?
.
Hmm but $p \rightarrow \neg q$ doesn't exist?
Merineth
It's just p -> s where s = ~q
Damn
You need to get used to forming variables for various things in your head
You can think of it as adding parentheses and considering "the whole thing in parentheses"
p -> (~q)
yeah that makes sense
i see what you did now
$r \land \neg q \land \neg p \lor \neg r \land p \lor q$
Merineth
I got to this point
i see some de morgan now
$r \land \neg q \land \neg (p \land r) \land p \lor q$
Merineth
$r \land \neg q \land 0$
Merineth
And because of this rule where p and negative is 0 means the entire thing is negative
Careful, "and" typically has a higher precedence than "or", meaning you need parentheses around both "or" here
Yeah i'm having it tought identifying when i can use paren or remove
Looking at that, it seems you pretty much can't remove parentheses ever, just move them around via associativity
But it's pretty restrictive
If you understand what you're doing, it's much more practical to remove parentheses in cases like p n (q n r) or (p u q) u r because that's what associativity gives you
But p n (q u r) is not the same as p n q u r
Look at the boolean algebra part, it's obvious that a + (b + c) = a + b + c and so on
It works the same
Yeah but me removing
only increases the risk of me doing wrong :I
I really despise when they include a excercise in the book but there is no solution at the end..
Assume that q is true (1) and that the statement is true. Determine p r and s
$(q \rightarrow (\neg p \lor r ) \land \neg s ) \land (\neg s\rightarrow \neg r \land q)$
Merineth
Before i start using the formula i can conclude that if i want to determine p r and s and that the statement is true.
Then both sides of the and symbol has to be true
$(q \rightarrow (\neg p \lor r ) \land \neg s )$
Merineth
$(\neg s\rightarrow \neg r \land q)$
Merineth
As in these two parts have to both be true
Yeah
Okay I’ll try that
The fact that they didn't put parentheses for the implications is pretty bad but I think we can assume that p -> q n r is p -> (q n r)
$\neg q \lor ((\neg p \lor r ) \land \neg s ) \land (s \lor ( \neg r \land q ))$
Merineth
This is what i got after swapping the rightarrow with it's equivalent
You're missing a set of parentheses
i am?
$\color{red}(\color{black}\neg q \lor \color{green}(\color{black}(\neg p \lor r ) \land \neg s \color{green})\color{red})\color{black} \land (s \lor \color{green}(\color{black} \neg r \land q \color{green})\color{black})$
Nel
You correctly added the green ones but removed the red ones
Ah i see
(odd that coloring in white makes it black and vice versa)
Sure
$( \neg q \lor (( \neg s \land \neg p ) \lor ( \neg s \land r ))) \land ((s \lor \neg r) \land (s \lor q ))$
Merineth
I forgot the question
Ok so
$E = (q \rightarrow (\neg p \lor r ) \land \neg s ) \land (\neg s\rightarrow \neg r \land q)$
Nel
E = 1, q = 1, find p,r,s
You can actually just start by substituting q
$E = (1 \rightarrow (\neg p \lor r ) \land \neg s ) \land (\neg s\rightarrow \neg r \land 1)$
Nel
$E = ((\neg p \lor r ) \land \neg s ) \land (\neg s\rightarrow \neg r)$
Nel
$E = ((\neg p \lor r ) \land \neg s ) \land (s \lor \neg r)$
Nel
I'd say just apply de Morgan's here
Oh I see.. I could’ve just substituted q with 1 immediately
Yeah
It doesn't matter too much though, you can very well use what you arrived at
$E = ( 0 \lor (( \neg s \land \neg p ) \lor ( \neg s \land r ))) \land ((s \lor \neg r) \land (s \lor 1))$
Nel
$E = (( \neg s \land \neg p ) \lor ( \neg s \land r )) \land (s \lor \neg r)$
Nel
How could you remove the 1 at the start?
I see what you mean with it being 0
If you translate it into ~1 u q, it's 0 u q = q
Merineth
No, why would it be?
$0 \rightarrow (\neg p \lor r)$
Merineth
s has to be 0, yes, but if r is 0 and p is 1, you get a (0 and 1)
This is always true
0 -> p is always true, but that's a different story
It's so hard keeping track of everything
Hmm ok let's get back to this
Remember the kettle? "if the kettle is boiling, then there is water inside". Now you know that "the kettle is boiling" is true, so "there is water inside" is true as well
Does that make sense?
Yeah i guess
it's just so unbelivably complicated to keep track of everything
I despsie when i have to "guess" and there isn't any method behind what i do
$(1 \rightarrow (\neg p \lor r ) \land \neg s ) \land (\neg s\rightarrow \neg r \land 1)$
Merineth
This is what i start with
That's basically intuition
Yes
$(1 \rightarrow (\neg p \lor r ) \land 1 ) \land (1 s\rightarrow \neg r \land 1)$
Merineth
Can i write it as such now?
I can also see that r cannot be 1
Yeah
that also implies p has to be 0
Yes
Okay so it isn't a rigorous exercise it's more of a "see" question?
I’m just worried that a similar question appears on the exam and I won’t be able to see it at all
Do you understand how to get to this point?
Yes
Then you can rearrange the expression:
$E = \neg s \land ((\neg p \lor r ) \land (s \lor \neg r))$
Nel
You have E = 1 so by that same rule of p n 1 = p you can deduce ~s = 1 hence s = 0
That's basically how you solved it, just a little more rigorous
Right so you get
$E = (\neg p \lor r ) \land (0 \lor \neg r)$
Nel
Nel
Same thing but for ~r which gives r = 0
ooh neat
And you're left with E = ~p
So ~p = 1, p = 0
It might be more rigorous to say 1 <=> ... instead of E = ... everywhere
I'd say it's a matter of taste honestly
Like it may matter in higher order logic or something but not here
Yeah i see what you mean
It isn't to hard
Luckily got some easy "prove" questions
$\neg (p \land ( \neg p \lor q )) \Longleftrightarrow \neg q \lor \neg p$
Merineth
$\neg p \lor \neg ( \neg p \lor q )) \Longleftrightarrow \neg q \lor \neg p$
Merineth
$\neg p \lor (p \land \neg q )) \Longleftrightarrow \neg q \lor \neg p$
Merineth
Well here comes the problem again when i'm unseure if i'm allowed to ignore parentheses
$\neg p \lor (p \land \neg q) = \neg p \lor p \land \neg q$?
Merineth
If that is true then i can solve it but not otherwise
How do you solve it if it's true?
Merineth
Right so this is why precedence matters
$\neg p \lor (p \land \neg q) = \neg p \lor p \land \neg q \neq (\neg p \lor p) \land \neg q$
Nel
The first two are exactly the same thing when you consider "and" to have higher precedence than "or"
(which is typically the case)
Your material doesn't deal with precedence though, so if you don't want to deal with it either, don't remove the parentheses
No the second one is a "and"
mb
Merineth
This is what i meant
From this, yeah you're correct
$\neg p \lor (p \land\neg q) \Longleftrightarrow\neg (q\land p)$
Merineth
So this is the point i get stuck at
Distribute
aaaaaaah ofc
totally missed that one
$(\neg p \lor p) \land (\neg p \lor \neg q) \Longleftrightarrow\neg (q\land p)$
Merineth
Ye
Well you're one de Morgan's away but ye
Yea
nice
Completely forgot about distributive
When a question tells me to "negate"
what do they mean?
Negate and simplify : \
$p \land q \rightarrow r$
Merineth
I guess just ~(p n q -> r)
oh damn
How do you understand that ? D: I dont even know what they are asking for when i'm given a question like that lol
I mean it seems a little stupid, can you screenshot that question?
Yeah
it's 15.20
It literally translates to "Negate the following statements and simplify the results"
$\neg r \land (p \land q)$
Merineth
This is what i got but idk if it's right
Oh nvm they had the answer in the book
and it's correct?
Kind of an ass question, no?
Yeah
Shesh the next question asks me to form my own statement based on text....
does that seem normal?
I don't know I guess they felt like writing "negate and simplify E" instead of just "simplify ~E"
Understanding the language I suppose
Why do they have different rows*?
Can this be written on a single row?
everything above t and then long left and right arrow t?
With "and" symbols to connect each row, yes
It's written as a list and a conclusion
If we have:
- a
- b
- c
then: - d
Oooh okay
That's sooo odd tho, it isn't even mentioned in the book but he just started using it on the exams
Guess i'll just have to remember that
∴ means "therefore": https://en.wikipedia.org/wiki/Therefore_sign
Yeah i assumed so but good to know
https://en.wikipedia.org/wiki/Logic
Look at the first image
It translates in english to:
- we know p is true
- and we know that "if p is true then q is true"
- therefore we can conclude q is true
Merineth
Is r supposed to be q?
no
Oh never mind
That's what got me hung up also
L5 followed by L4, yeah
Of course
Merineth
$(p \rightarrow r) \land (p \land s) \Rightarrow r$
Merineth
Not sure how i handle the s tho
since s isn't listed on the formulas
I can transoform p into p V q
It's L5 again
$(p \rightarrow r) \land ((p \land q) \land s) \Rightarrow r$
Merineth
Like so?
Merineth
$(p \rightarrow r) \land (p \lor q) \Rightarrow r$
Merineth
L_1?
L1 from here, yes
That doesn't help
might be a weird question but
i cant go from right to left right?
Considering the right arrows?
$r \Rightarrow r$
Merineth
Yeah i had a suspicion that was the case
Just had to verify
Well either way i've been at it for like 4.5 hours now and i can feel my concentration drifting 
=> is "implies" while <=> is "if and only if"
I'll continue from where i left of tomorrow + start with induction if you are good with that :P
Well i am glad when you are ^^

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Help 5 b
,rotate
I have gotten the equation 2sin (3x) -1
but how do i find p when Y =0 ?
<@&286206848099549185>
@quiet reef Has your question been resolved?
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I know what injection, surjection, and bijection is, but how do you prove a function meets some or all these properties?
For a small set of numbers in the domain and codomain is easy, just look for examples where it isnt true
but for larger sets it becomes less obvious
do you have an example?
not an example of proving a function but an example of coming up with a function

