#help-27
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When finding hessian matrix are f12 and f11 always the same
no
Closed by @lofty monolith
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if you mean f21 and f12, then yes
most of the time anyway
as long as they are continuous for example
this result is called schwarz's theorem (among other names) @lofty monolith
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0 = root of g*sin(theta)*d+v^2
Can can isolate for theta here?
I dont think i am allowed to square both sides sinces 0^2 = 0
that not any issue
But that's also unnecessary, you'd ideally first solve for sin(theta) and eventually theta.
0 = root of gsin(theta)d+v^2
will be the same as
gsin(theta)d+v^2
surely not
i mean you can subtract both side by v^2 then take power of 1/2 both side
Huh?
how can i subtract that
is that whole thing under a root?
yes
$\sqrt{x}=0 \iff x=0$
artemetra
why not
why do u think so
$x=0 \iff x^n = 0$
artemetra
for any n≠0
??
actually nvm im stupid
so what's the issue
-v^2/-2gd
= sin (theta)
i put the wrong equaiton this is the equation after squarring on both sides
right?
@restive river Has your question been resolved?
Whats the equal to sign with arrows on either side mean?
@restive river Has your question been resolved?
if and only if
looks correct
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this is called ambiguous language
a prime number is odd
i claim this is true because 3 is odd
what do you mean by the statement "a prime number is even"?
and why have you assigned it a truth value of F?
that's true
because like I said, 5 is odd so... a prime number is odf
"it"
what is "it"
your statement: a prime number is odd is true, because there is a prime number (3) that is odd
"the" prime number... so you've picked one?
all you asked so far was whether any prime numbers were odf
which yeah there are many in fact
look into "for all" or "for every" qualifiers
and "for any" or "for some"
no, I mean like saying:
for every prime number p, p is odd or p is even
well, it might be more clear that the breakdown that you wrote out earlier doesn't make sense
this breakdown
"for all prime p, (p is odd) or (p is even)" is not equivalent to "(for all prime p, p is odd) or (for all prime p, p is even)", that's what hayley is saying
let's even drop the prime assumption to have a clearer example
"for all integer p, (p is odd) or (p is even)" is not equivalent to "(for all integer p, p is odd) or (for all integer p, p is even)"
it's true
all integers are either odd or even
that also works for primes
yes
indeed
why should PvQ be equivalent to "for all prime p, (p is odd) or (p is even)"
you made the for all completely disappear
and the crux of the problem is exactly the for all
^
you're right, you can intepret it as false
like you 've shown
(all primes are odd) or (all primes are even) is false
you can intepret it that way, it's just english words
yeah
you're using words, you expect it to be possibly ambiguous
what's the problem
what's your point frog ? we're trying to formalize their statement
you can't expect anyone to care about that
the convention is that you interpret it the other way
i mean that if you say that you interpreted it wrong because it's english words and you can't exclude this interpretation, it's unlikely to convince anyone
i don't know what you mean
i didn't like read the entire conversation
what's P
it's true
it's true
it's that statement
yes
(all prime numbers are even) is false
(all prime numbers are odd) is false
(all prime numbers are (even or odd)) is true
the third statement is not the logical disjunction ("or") of the first two
"(all prime numbers are even) or (all prime numbers are odd)"
which is false
as expected
"a prime number" is fairly ambiguous -- do you mean some prime number or every prime number?
"a prime number" is fairly ambiguous -- do you mean some prime number or every prime number?
"a number is equal to 17" is that statement true or false?
"a number is equal to 17" is true, by your reckoning?
no
there exists a number that is 17
but not every number is 17
so does "a number is equal to 17" have a truth value or not? and if so, what is it?
you said "P : A prime number is odd" at the beginning
you can't say this in the first place, it sounds weird
a numebr is equal to 17 is the same thing
i'm asking you because you're the one who is insisting on using this "a" statement
it doesn;t have a conventional meaning
when i read the original question, it seems to me that it should be read as "every prime number is either odd or even"
but there is a universe in which it means "there exists a prime number that is either odd or even"
"A prime number is either odd or even" is a normal thing to say, it has a conventional meaning, when there's "either"
no it's not
"everything in the world is either cheese or not cheese"
would you agree with this statement?
that's ambiguous tbh
ok fair cheese is a bit of a fuzzy boundary
what do you mean by "a prime number is odd" though
it sounds like you mean "every prime number is odd"
programmer, right?
do you know any programming languages?
their logical disjunction would be "every prime number is odd, or every prime number is even"
which is false because it's the disjunction of two false things
"every prime number is either odd or even" means that if you handed me a prime number, I would be able to say, "yes that prime number is either odd or even"
"every prime number is either odd or even" is true
"either every prime number is odd, or every prime number is even" is false
these statements are not the same
oh
well
it's not
if the teachers said that "every prime number is either odd or even" is equivalent to "every prime number is odd, or every prime number is even" then that is incorrect [at least by most reasonable interpretations of those words]
ya
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is this tending to infinity?
looks like it
divide by 6^x in numerator and denominator, and it seems like it is tending to infinity
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On the graph of x^2 is x=0 an inflexion point?
Or just an extreme point
So inflexion points are found when the second derivative at that point is 0?
And extreme points when the first derivative is 0
Si this isnt enough?
yep that's not enough
e.g. f(x) = x^4
f'(x) = 4x^3
f''(x) = 12x^2
f''(x) = 0 if x = 0 but that's not the inflection point
So what do in need more
f'' has to change its sign at the point
Ok
and hence here
12x^2 is nonnegative
it means f(x) is concave up on the entire domain
and no inflection points exist
@neon folio Has your question been resolved?
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because its exponential not polynomial
when the x is in the exponent the formula is $\frac{d}{dx}a^x=\ln{a}\cdot{a^x}$
HadarS
@restive river Has your question been resolved?
No power rule means derivative of x^n is nx^(n-1)
Right
Correct
Why should it?
2 is just a constant scalar
It’s multiplying the expression you can just take it out of the derivative
Are you asking why the 5 disappears but not the 2 in this question
Then it’s because we’re adding the 5
If it was 5•x^2 you’d get 10x
Np
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help how do I find the coordinates? my teachers didnt teach us how to
or answer the drawing room coordinates
@cobalt torrent Has your question been resolved?
<@&286206848099549185>
Use the coordinate graph?
im confused on the drawing room part
help
🙂
helpppp
@cobalt torrent Has your question been resolved?
hello
the center of cordinate is 0,0
if you go down the right part goes down too
so you must count the squares until each point, and then decide if its positive or negative. You can decide wheter its positive or negative before or after which ever one you prefer
so is the drawing room 2 and 8?
wait the question isn't asking to get position of the points
its asking why this would be useful
oh
image is that of a floor of your house ig
useful because you dont need to guess how much carpet you would need to cover the floor
you can use math
oh
then starting from origin, you count the squares
you must move with l's
you cannot make a straight line because you want to count x and y
oh ok thanks
type .close to close this help channel, and its great u understanding now ! very god
.close
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What is the force body diagram for a bike going in a straight like that's accelerating?
@floral cradle Has your question been resolved?
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<@&286206848099549185> I dont know how to calculate the area with all these nuimbers! help
Try to split the shape up
What shapes would be easier to calculate the area with?
2 rectangle
Ain’t no way 💀
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Break that shape into easier shapes that you can find the area of
Like the two rectangles
how old are yoou
It's not
sorry, the school system where I come from doesnt teach anything
its not?
length times width
How did you spilt the shape?
2 recs
Where did you split it at
top and bottem
the place where it sticks out and the big rectangle
wait I think I know 5-1 because the 5 is not the width or length anymore
did u subtract 7 by 3?
Yes
Exactly that
oh
19?
yes
tysm
im sorry canadian schooling is terrible
they dont teach but assign it thinking we know it
ty
also make sure to type .close
.close PS ty again
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not sure what i'm doing wrong here
just plug in 12 and 3 here and don't do the rest
oh do i not need to sub in the u value
if you do this, then there's no need to change the integral bounds
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Can someone show me that the definite integral is f(b) - f(a)
using a graphical method
!original
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I want to visualize why it is f(b) -f(a)
I mean, why isn't it f(b) + f(a)?
it's in the proof
if you haven't taken differential or integral calculus, it isn't gonna make much sense
give an example to find M. A + M = N, so A = N - M. I can't see this in the context of integrals with Barrow's Rule. Can you explain this in a visual way?"
what are you talking about
What are A, M, and N?
read the proofs here
https://en.wikipedia.org/wiki/Fundamental_theorem_of_calculus
@jolly swan Has your question been resolved?
thx
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How do i simplify
,rccw
what have you tried thus far
Is it right
cscx isnt the same as cos x no
Oh
I didnt notice it was csc

So is it csc instead
yeah
Is that simplist form
nope
seems okay so far
there is more you can do ig
were you asked to make it into something specific?
Just sats simplify
just debating whether splitting the fraction would really be considered 'simpler'
we can do it if you want, even if for nothing but a fun exercise
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So for the question here
It wants 6 subintervals over the interval [3,7]?
I just want to make sure I'm interpreting this right
or the other option is that it wants 5 subintervals
Ah I got it it is 6
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The value of a car depreciates at a rate of 12.5% every year. Determine how long it will take the car to be worth its original value.
the formula my teacher gave me was a=p(1+-r/n)^nt
ik you would plug in 0.125 for r
but idk what to do after that
a=amount after a certain amount of time
p=principal amount
r=rate
n=number of compounds and t= time in years
the question doesn't make sense, it should say 60% its orginal value or something
okay
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I am trying to solve this ODE using laplace and im lost on how to proceed
split Y into a sum of two fractions
partial fraction decomposition?
@slate raptor Has your question been resolved?
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I got the derivative and second derivative right by how can I find where the function is increasing and decreasing
solve P'(x) = 0 and create a variation table
Thanks and the last question I couldnt' complete was this one, for the function 2sin(x) + x, how can I find the transition points
I looked at the graph, tried the inflection and critical points
used chegg, gpt, and a bunch of other things but none of them were right
ignore the -1/2 was just a random try
here is the graph
the min is lower than the -2 out of the interval
There are three kinds of transition points, they are point of local maxima, point of local minima and inflection point.
in short you are basically finding extrema of the function within certain range
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Hi, I'm stuck with the scenarios where $x_1<x_2$ in the proof above, I'm not sure where exactly to go from there
GratedRacer08
I'd let $a = x_1+x_2$ and $b=x_3+x_4+x_5$, so $a+b=50$. Then you can show that $3a \leq 2b$ and go from there.
Ari
It has to be a proof by exhaustion, for this assignment
oh
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<@&286206848099549185>
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how do you solve the derivative of absolute values? like
solve it both for x > 0 and for x < 0
remember that d/dx 1/x is ln|x| so you don't have to worry about absolute values
@spring bison Has your question been resolved?
wait so whats the derivative of ln(|x|)
and why wont i have the worry about the absolute value
ik d/dx ln(x) = 1/x, would it be the same regardless of absolute value symbols?
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so
\this is on the top of numerator
i am graphing asymptotes stuff like that
And i need x intercept
so i set the numerator which is 4x^2-36=0
and i got 4(x-3)(x+3)
so is it only -3,0 and 3,0
or 4,0 3,0 and -3,0
depends on the denominator
no that can't be right
if the denominator is also equal to 0 when the numerator is 0, then it's not an asymptote, it has no value
yeah this is correct
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is the answer given here wrong? in the expansion of (7-4i)(2-i) i get -4i^2 which i thought was +4, but it's written as -4
fuck nevermind, i just realised i missed the negative hahah
though i was wondering if it was appropriate to treat -i^x as (-1)^x * i^x generally
-i^x questions were a bit confusing to me
just leave it as -i^x
alright yea, that makes sense, i think i was just overcomplicating things in my head. sorry ive been studying all day hahah
thank you though
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Why is the hole only x=0 and not x=0 and 1
Don’t x-1 and x cancel out
Please @ me when someone gets here
@bitter patrol Has your question been resolved?
@toxic cargo because at x=1 function tends to infinity, at x=0 function tends to 0 which is exist but not equal to 0 so there is hole for the value x=0 learn some basics of limit , or draw the graph of (x-1)/(x-1)^2 you got your answer further more the question is about holes not discontinuity if it was then both be the answer
are you clear?
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How to solve 59049=3^n-1
Repeatedly divide by 3?
ok so using logs is the easier way
Well yeah if you have a calculator
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<@&286206848099549185>
Just take limit as $x\rightarrow\infty$
Marin Kitagawa
root(4x-2/x)/1+1/x
which goes to root(4x)/1
but how do I take the square root of 4x? Is it just 2?
You're so close. But The terms inside the square root is wrong. Clue: $x = \sqrt{x^2}$. So, will it still be $4x$ inside the root?
Marin Kitagawa
hm. When finding the limit wouldn't it be sqrt(4x^2/x-2/x) for the numerator
You have to divide by $x^2$ inside the root even though you're dividing numerator and denominator by $x$. Because, as said, $x$ becomes $x^2$ inside the root
Marin Kitagawa
i see
so the final answer would be 2 because it simplifies to 2x/x
or is that wrong?
Yes. You're right. It'd simpilify to $2$. So, the horizontal asymptote will be $y=2$
Marin Kitagawa
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Is it divergence or convergence
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find a number where:
number < 10.000.000 and number > 1.000.000
Number = (sum of digits of number)^2 = rootOfNumber^2
Do not end in 0,
root is an integer
Can someone help me find such number I have been struggling 😭
roof of number? wdym?
sqrt()?
yeah the root
for instance:
$\sqrt{x}^2 = x$
artemetra
1296 = (1 + 29 +6)^2 = 36^2
so what's the point of writing Number = rootOfNumber^2
^
oh
find a number than verifies this
i see
cuz 1 + 29 + 6 = 36
wait why 29
1296 , 1 29 6
1+2+9+6
yeah it could also be 1+29+6
oh so it could be any one of them?
interesting
well there are 8 possible combinations of these
one of them is trivial
$2^{\log_{10}(n)}$
artemetra
combinations
yes
if it's not very easy to find I don't really mind it, I am doing an assignment and I need to find such numbers, However I have a problem in my program and I need an example number in that range to calculate it
I just came and asked just in case there is any trick other just bruteforcing
well the first filter is that number must be a perfect square
that's already much less numbers to consider
but tbh idk a rigorous way to find this
Alright, thanks for help anyways
the different combinations of digits is what trips me up
Yeah it's very confusing
Can I show you my output of my program? I tested for a number to see if it checks all of the combinations, it seems though it doesn't?
well let me change the output to make it more clear
Code is pretty chaotic
Debug: N=9991921, root=3161, sum=0, d=991921, b=9, i=6, j=6
Debug: N=9991921, root=3161, sum=0, d=91921, b=99, i=6, j=5
Debug: N=9991921, root=3161, sum=0, d=1921, b=999, i=6, j=4
Debug: N=9991921, root=3161, sum=0, d=921, b=9991, i=6, j=3
Debug: N=9991921, root=3161, sum=0, d=21, b=99919, i=6, j=2
Debug: N=9991921, root=3161, sum=0, d=1, b=999192, i=6, j=1
Debug: N=9991921, root=3161, sum=9, d=91921, b=9, i=5, j=5
Debug: N=9991921, root=3161, sum=9, d=1921, b=99, i=5, j=4
Debug: N=9991921, root=3161, sum=9, d=921, b=991, i=5, j=3
Debug: N=9991921, root=3161, sum=9, d=21, b=9919, i=5, j=2
Debug: N=9991921, root=3161, sum=9, d=1, b=99192, i=5, j=1
Debug: N=9991921, root=3161, sum=18, d=1921, b=9, i=4, j=4
Debug: N=9991921, root=3161, sum=18, d=921, b=91, i=4, j=3
Debug: N=9991921, root=3161, sum=18, d=21, b=919, i=4, j=2
Debug: N=9991921, root=3161, sum=18, d=1, b=9192, i=4, j=1
Debug: N=9991921, root=3161, sum=27, d=921, b=1, i=3, j=3
Debug: N=9991921, root=3161, sum=27, d=21, b=19, i=3, j=2
Debug: N=9991921, root=3161, sum=27, d=1, b=192, i=3, j=1
Debug: N=9991921, root=3161, sum=28, d=21, b=9, i=2, j=2
Debug: N=9991921, root=3161, sum=28, d=1, b=92, i=2, j=1
Debug: N=9991921, root=3161, sum=37, d=1, b=2, i=1, j=1```
This is for 9991921
Let me rearrange the print so it's like digit1+digit2+...
Combination trying: sum=0 + (991921 + 9)
Combination trying: sum=0 + (91921 + 99)
Combination trying: sum=0 + (1921 + 999)
Combination trying: sum=0 + (921 + 9991)
Combination trying: sum=0 + (21 + 99919)
Combination trying: sum=0 + (1 + 999192)
Combination trying: sum=9 + (91921 + 9)
Combination trying: sum=9 + (1921 + 99)
Combination trying: sum=9 + (921 + 991)
Combination trying: sum=9 + (21 + 9919)
Combination trying: sum=9 + (1 + 99192)
Combination trying: sum=18 + (1921 + 9)
Combination trying: sum=18 + (921 + 91)
Combination trying: sum=18 + (21 + 919)
Combination trying: sum=18 + (1 + 9192)
Combination trying: sum=27 + (921 + 1)
Combination trying: sum=27 + (21 + 19)
Combination trying: sum=27 + (1 + 192)
Combination trying: sum=28 + (21 + 9)
Combination trying: sum=28 + (1 + 92)
Combination trying: sum=37 + (1 + 2)```
Here
does it try all combinations?
yeah I mean
whats the math trick to find how many combinations there are
for the number 9991921
.
basically 2^{number of digits - 1}
do you see why that's the case?
well I don't have 32 combinations here....
I don't know which ones im missing
Do you want my code?
what language
C
It's an algorithm so there's no tricky part in it
uint64_t checkFlawless(uint32_t root) {
uint64_t N = root * root;
uint64_t sum = 0;
uint64_t Stmp = 0;
int intLength = lenHelper(N);
uint64_t d, b;
uint32_t c = 1;
uint64_t tmp = N;
for (int i = intLength - 1; i >= 1; i--) {
for (int j = i; j >= 1; j--) {
uint64_t ten = powOf10(j);
d = tmp % ten;
b = tmp / ten;
Stmp = sum + d + b;
if (Stmp == root) {
return N;
} else if (N==9991921) {
printf("Combination trying: sum=%d + (%d + %d)\n", sum, d, b);
}
}
sum += tmp / powOf10(i);
tmp = tmp % powOf10(i);
}
return 0;
}```
although makes sense considering the need for speed
also what shouldn't end in 0
I just asked this in the specific question because my program can very easily find such number like a human can
ah okay
my program has errors for some reason finding more complex combinations and I don't know which combinations I'm missing
Does anyone here speak spanish?
??????????
Do u?
for the first loop:
we get the number 1296 and we start splitting it 4 times
1,296
12,96
129,6
I need help and my class is in spanish
mhm
for the second loop is where it gets tricky:
it saves the first digit in the sum
so sum = 1 (from 1296 -> 296)
and we apply the same algo
sum + 2 + 96
sum + 29 + 6
my idea was that if i make a loop from 0 to 2^{number of digits - 1}, the binary representation of each number within a loop will act as an on/off switch for the presence of a split or not
like
I thought of it
but
look in this situation:
1296 (we move the split)
1,296
12,96
129,6
until now good
when we go to 2 splits
1,2,96
12,9,6
and then
1,29,6
u need to split the commas and not move them together
this works with any splits
*any number of splits
1296 -> 4 digits -> loop from 0 to 2^3 -1
000 -- 1 2 9 6
001 -- 1 2 9,6
010 -- 1 2,9 6
011 -- 1 2,9,6
100 -- 1,2 9 6
101 -- 1,2 9,6
110 -- 1,2,9 6
111 -- 1,2,9,6
kinda
this will always yield all combinations
binary loop
and the number the binary loop gives us
is where to place the commas
thank you thank you
Alright I guess I can handle the implementation except if you want me to keep you updated hahaha
not sure tho how to effciently realize this in C
give me a second to think
ig you can make an array [1,2,9,6] into [1, 10, 2, 10, 9, 10, 6] where 10 is like a flag and then replace 10 with 11 where you need a comma and then parse the list
I don't think an array is needed wait
but the extra allocations feel unnecessary
oooOoOOOOooOOOOh i've got it (but i'll wait for you)
sum = 0;
num: 1296
010 -> ```
we can do a math trick to get the 12 add it to sum and then get the 96 and add it
oooooooh right
also
you can use them to determine when is the next number
010 -> is 1296 % 10^2 and 1926 /10^2
'hyperdigit' lol
yes
where 10^(location of comma)
No idea what that is but it sounds interesting
hahaha
oh, problem solving basically
yes lol
haha well I don't know if you are being serious or not, it sounds good but I have many studies now and I don't think I could really do that haha
nah i was joking
hahaha alright
thing is:
sounds good, how do I apply it in a loop for any number
what we have available:
powOf10(n) //returns power of 10 raised to n
lenHelper(n) //returns length of the number
basically:
length = len(str(1296))
for i in range(0, 2**(length-1)):
i see i see
to get every digit of a binary you do >> and % 2 in a loop
I get the digits going right or left?
for example
I have the binary number:
100
I'll get the digits as 100
or as 001
for i in range(0, math.floor(math.log2(n)+1)):
print(f"digit {i}:", (n>>i) & 1)
"& 1" is the same as "% 2" in this context
so
n = 1296
length = len(str(n))
for i in range(0, 2**(length-1)):
for y in range(0, math.floor(math.log2(n)+1)):
print(f"digit {i}:", (n>>i) & 1)```
well, something wrong
y is the digit
digit 0:
digit 0: 0
digit 0: 0
digit 0: 0
digit 0: 0
digit 0: 0
digit 0: 0
digit 0: 0
digit 0: 0
digit 0: 0
digit 0: 0
digit 0: 0```
That seems good
not i
ah
true
I didn't see that mb
n = 1296
length = len(str(n))
for i in range(0, 2**(length-1)):
for y in range(0, math.floor(math.log2(n)+1)):
print(f"digit {y}:", (n>>y) & 1)```
You're typing for so long it's scary hahaha
haha alright
i have an idea
loop over digits of n and digits of commas (at the same time) and have another counter of power. not sure how to explain it but i'll just show an example and i think you'll get it
initially:
n = 1296
suppose the commas are at 100 (so we should get 1,296)
sum = 0
power = 0
now, iterate from the back:
n%10 = 6
therefore increase sum by 6*10*power = 6*10*0 = 6 -> sum becomes 6
n = n//10
comma = 0
power++ (power became 1)
next step:
n%10 = 9
therefore increase sum by 9*10**power = 9*10*1 = 90 -> sum becomes 96
n = n//10
comma = 0
power++ (power became 2)
next step:
n%10 = 2
therefore increase sum by 2*10**2 = 2*10*2 = 200 -> sum becomes 296
n = n//10
comma = 1
oh shit, comma is 1
reset power = 0
next step:
n%10 = 1
therefore increase sum by 1*10**power = 1*10* 0 = 1 -> sum becomes 297
n = n//10
comma = 0 (assume there's another 0 at the front of every comma mapping)
power++ (power became 1)
this completes the loop
@snow sentinel
yep
thank you thank you
Let me try to make it in Python (First) xd
#1296
n = 1296
root = 36
def func(n, root):
length = len(str(n))
for i in range(0, 2**(length-1)):
n = 1296
c = 0
s = 0
for y in range(0, math.floor(math.log2(n)+1)):
last_digit = (n>>y) & 1
if last_digit == 1: c = 0
s += last_digit*(10**c)
n //= 10
c+=1
if s == root: return n
return 0
wait why s += 2*(10**c)
maybe s += last_digit*(10**c)?
ah yeah
mb
func(1296, 36)
0
:0
#1296
n = 1296
root = 36
def func(n, root):
length = len(str(n))
for i in range(0, 2**(length-1)):
n = 1296
c = 0
s = 0
for y in range(0, math.floor(math.log2(n)+1)):
last_digit = (n>>y) & 1
if last_digit == 1: c = 0
s += last_digit*(10**c)
n //= 10
c+=1
if s == root: return n
else: print(s)
return 0
uhh
s is always 1 for some reason
what does this give?
math.floor(math.log2(n)+1)
can't we just last_digit = (n>>1) & 1
wait I think I did something wrong oops xD
#1296
n = 1296
root = 36
def func(n, root):
length = len(str(n))
binary_len = length-1
max_comb = 2**(binary_len)
for i in range(0, max_comb):
n = 1296
c = 0
s = 0
for y in range(0, binary_len):
last_digit = (n>>1) & 1
if last_digit == 1: c = 0
s += (n%10)*(10**c)
n //= 10
c+=1
if s == root: return n
else: print(s)
return 0```
everything is 0 💀
number of digits in a binary number
but tbh it's unneeded
that's binary_len
oh no its not
wait
oh wait
yeah it is
lol
1296 -> 3 slots -> 3 binary, 2^8 different combs
where is my code wrong tho lol
ah
last digit is is not n >> 1
def sum_by_partition(n, commas):
sum_ = 0
power = 0
while True:
if n == 0:
return sum_
sum_ += (n%10)*10**power
n //= 10
if (commas & 1) == 1:
power = 0
else:
power += 1
commas >>= 1
ta-da
this works
why?
36*36 = 1296
ah
aah
wait let me combine them
ah mb
wait
def sum_by_partition(n, commas):
sum_ = 0
power = 0
while True:
if n == 0:
return sum_
sum_ += (n%10)*10**power
n //= 10
if (commas & 1) == 1:
power = 0
else:
power += 1
commas >>= 1
def checkNumber(N, root):
total_commas = len(str(N)) - 1
for comma in range(2**total_commas):
sum = sum_by_partition(N, comma)
if sum == root: return N
return 0
print(checkNumber(1296, 36))```
Seems to be working like a charm :))
Let me convert it to C
this ran really quickly in python actually
Thanks!
no problem, this was fun
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
uint64_t int_pow(uint64_t x, uint8_t y) {
uint64_t temp_x = x;
while (y > 1) {
x*=temp_x;
y--;
}
return x;
}
uint64_t sum_by_partition(uint64_t N, uint8_t commas) {
uint64_t sum = 0;
uint8_t power = 0;
while (N != 0) {
sum += int_pow((n%10)*10, power);
n /= 10;
if ((commas & 1) == 1) {
power = 0;
} else {
power++;
}
commas >>= 1;
}
return sum;
}
uint64_t checkNumber(uint32_t root) {
uint64_t N = (uint64_t) root*root;
uint8_t total_commas = lenHelper(N) - 1
uint64_t sum;
for (uint8_t comma = 0; comma < int_pow(2, total_commas); comma++) {
sum = sum_by_partition(N, comma);
if (sum == root) {
return N;
}
}
return 0;
}```
Looking good haha
ah shit I have done something wrong idk
I don't have anything different wtf any ideas? @frozen aurora
uh
ah
lenHelper(N) - 1
for some reason lenHelper returns 7
wtf how
ah wait
I give the N not the root
wait mb
uhh
comma=0
1550
there's something wrong in sum_by_partition
I think
we can't really use >>
while(true)
causes buffer overflow and probably reads other numbers :>
no wait wat
@frozen aurora
Help
trilon@AK-47:~/flawless$ pypy flawless.py
('hello:', 6)
('hello:', 90)
('hello:', 200)
('hello:', 1000)
('hello:', 6)
('hello:', 9)
('hello:', 20)
('hello:', 100)
('hello:', 6)
('hello:', 90)
('hello:', 2)
('hello:', 10)
('hello:', 6)
('hello:', 9)
('hello:', 2)
('hello:', 10)
('hello:', 6)
('hello:', 90)
('hello:', 200)
('hello:', 1)
('hello:', 6)
('hello:', 9)
('hello:', 20)
('hello:', 1)```
added this print: py awaw = (n%10)*10**power print('hello:', awaw)
okay
focus on these 4
('hello:', 6)
('hello:', 90)
('hello:', 200)
('hello:', 1000)```
these first four are iteration for 000,
alright?
sum = 1296
for C now...
calc=60
calc=90
calc=400
calc=1000
third iteration is 400 ???? (instead of 200)
first is 60 (instead of 6)????????
I found the shitty little ass hole
@frozen aurora
python: py (n%10)*10**power
it does first the raise to power, then the multiplication
god dammit
I was like: why does he multiply by 10 and then I realized...
huh?
um
yea
oooooh i see now what's wrong with the C code
yes
Alright it works
i think
haha
o oh
it doesn't
almost there!
I get the number: 489984803178
for 1 10000000000
My teacher gets: 499984803178
How is that even possible
the difference is : 1000000000
which doesn't have a root
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How would it be possible that x=0 is a c.p,if f is increasing through it?
Think about f(x) = x³
@dire python Has your question been resolved?
Can someone help me with this task pls:
Determine all integers n for which real numbers x,y exist in such a way that the following equations are satisfied:
x+y=n
x³+y³=n²
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can someone help me with this
The graph of the function f(x)=2∣x−1∣−1 with Df =⟨−3;3⟩ was translated in parallel by a vector, resulting in the graph of the function g with the domain Dg=⟨−5;1⟩ and the range g(Dg)=⟨2;10⟩. Provide the translation vector and the formula for function g.
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
- I don't know where to begin.
Start by finding the range and domain of f
Then consider how ||they were shifted to get g||
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how to solve the quadratics formula give a hard example
What do you mean solve the quadratic formula
Ax^2+Bx+C=0
don't use help channels to ask for questions for you to do
.close
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Does anyone have an idea on how to solve this?
@indigo stag Has your question been resolved?
<@&286206848099549185>
substitute x=-10pi/3
I did that and I got 8.675, is there anything else i have to do? because the question is worth 4 marks?
no, you have to express it in an exact form
show your work (aka don't just substitute into calculator)
sorry im still kind of confused my teacher kind of just gave us this assignment but never went over this in a lesson. alright so after put x=-10pi/3 into the equation do I just simplify it?
yes
This is what I have right now, I feel like it’s wrong
and the result of that is 0
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<@&286206848099549185>
@indigo stag Has your question been resolved?
@indigo stag Has your question been resolved?
@indigo stag Has your question been resolved?
impossibile
i tried doing the graph
and there's no matching point
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this is what i have so far
how do i put these in interval notation
and how do i start on the 3rd question?
is this right?
i believe a bar symbolizes absolute value?
Yes
Yes
okay ty
Though it won't always work
Imagine if there was an x on the RHS but not on the LHS
If you subtracted that, then you'd have it on the LHS
So the better technique in that case would be to break it up
In this case, your method is faster
E.g. $|2x - 7| < 9 + x$
What would you do now?
Subtract x?
But then you'd still have -2x on the LHS
Also, why do you need the number line?
The inequality tells you x must be between 3.5 < x < 8
Why say x < 3.5 is false? Of course it is false
oh the number line is required
Ah, so the exercise asks you to draw one
yes
Well, then I'd still leave out the table
thats also required 😭
Correct the 0 to -9 though and you'll have a different result
i see
i’ll keep these in mind
yeah we were asked to look at it that way
cuz im actually just in 9th grade
Well, it's not like the inequality version is too hard for 9th grade, lol
i know.. i do agree that some of these are redundant tho 😭
anw i’ll try solving with -9 now
@ember cargo Has your question been resolved?
can i get help with the 4th one now?
Do the two cases like above
Is this a test, btw? (1 point each)
like this then?
extra credit
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@ember cargo Has your question been resolved?
<@&286206848099549185> i just need to know if the sign is right 😭
is it actually supposed to be greater than or equal to
the sign is correct.
no solutions then?
first equation | 2x - 5 | ≥ 3 that means: 2x - 5 is greater than or equal to 3, 2nd -3 ≥ 2x - 5 ≥ 3 This means that 2x - 5 is between -3 and 3
These two equations are equivalent
but as per the signs, it must be less than -3 and greater than +3?
how tho
the signs are reversed when you multiply or divide by a negative number
f example if you have a > b then -a < b bcuz multiplying both sides -1 changes the direction of inequality
to solve for x you need to add 5 to all sides then divide by 2
4 ≤ x ≤ 1?
no solution then?
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For a natural number n, P(n) is the product of its different digits of 0.
For example, P(2023) = 2 · 2 · 3 = 12.
Determine how many four-digit numbers n with the property P(n) = 12 exist.
find factorisation of 12
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Whats the formula to calculate derivative of si x^cosx
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please ignore the horrific hand writing 😓 just provign the limit of a sequence here and I was wondergin why my prof stopped at this step
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Guys, how do I solve this question?
How do you even begin to analyze a recursively defined sequence?
You might try and see if its increasing/decreasing and bounded above/below
I checked
Have you done linear algebra?
it is decreasing except in the first 3 terms
I'm doing it in uni rn
but this question is from analysis class
It might be overkill but you can represent this as a matrix, where you multiply the vector (a0, a1) with different powers of the matrix to get the nth term
this works better probably

