#geometry-and-trigonometry
1 messages ยท Page 272 of 1
right?
what i did on the second one was a-r plus b-r
to get c
c=b-r+a-r
=a+b-2r
no
Anyone willing to try this problem I made? If everything's correct, it shouldn't be too hard!
Answer: ||72ยฐ||
Note: ||Knowing this answer might make the problem too obvious ๐ฌ ||
I'll do that!
OOooh ๐
Xi, here's a small hint: ||Take a look at the equal sides||
๐คญ
xD
@upper karma
it's using cos because the graph starts from the bottom and rises
it's always a good idea to draw out the graph (like I did)
i said that it was -sine
it starts off at the vertical displacement
sin starts from 0, cos starts from 1
-sin means -0 ๐
but i started off somewhere different
thats why
-cos means -1
shit i meant
sine*
I started off at the vertical displacement
and then it goes up to 87
and down to 41
as for the period
I thought its pi/10
where did 10 come from?
sorry
the period itself is pi/10
the period is 12 months
i meant thats the value of B
I meant
the period is 20
there's no 10
well look
there's no 20 either ๐
pause
let me explain
from month 2 -> month 12
thats 10 months
and only half a period has occured
it repeats every year... the period is 12 (12 months)
mmm
ur right
i was under the assumption that
its a sine function
but I did not know at what x value the vertical displacement would occur
so i assumed it was 45
sine would start from the midline
yea
the midline
but i didnt know where the midline would be
it's easy
add both values, and divide by two
yeah
but i didnt know what the min was
i assumed that it could go lower
the question never stated that
but cuz its 12 months
it should be obvious that its lowest is at 41
and highest is at 87
well, they tell you the temperatures for every month, and it doesn't go under 41, hence "41" is the min
ya
i just didnt fully interpret that problem
correctly
my bad
ty
sure thing
@night karma
Why 1 tho? @upper karma
it would've worked with any number (used as a placeholder), but 1 was divided evenly by sin(90)
(which is also 1)
so sin(90)/1 = 1/1 = 1
it just simplifies things
Did you just made a sine from a 90ยฐ
Wow
Its smart and weird at the same time
and now that I think about it, it's more like 76, since alpha = sin^(-1)(0.7) is closer to 44 degrees
it's only for demo purposes ๐
So you dont get the right answer, do you
sin^(-1)(0.707) is 45 deg
And the answer its supposed to be 72
Not 75
but without that extra 0.007, you get closer to 44
which results in 76
180-(44+60)
And the answer its supposed to be 72
.
I don't know what to tell you ๐
I mean
numbers don't lie
anyone know the solution to this? i ended up with 35 but the correct answers i 45. can anyone help me out?
and I'm 99% I did it right
So you assume your method is correct, but bc of so many approximations, you got 76 maybe?
I also got a similar approach to yours
๐
Answer me lol
Maybe its bc of that
Dunno, while working out my problem, I found 72ยฐ ๐คทโโ๏ธ
Look it up
And you'll see
@upper karma @night karma
math checks out
@wanton lake then you come back
ahhh kk
Got it?
im working on it
@upper karma it might be you correct and him wrong lol imagine
But that'd be weird bc his way seems correct as well
also for 76 if you're declaring angle alpha closer to 44 deg:
so, yeah
@wanton lake lmk if you got anymore doubts
ok i will thx!
Np!
Exactly, that's why it's interesting. You think the figure might be indefinite?
It's quite close.. but still
DSpider:
Compile Error! Click the
reaction for details. (You may edit your message)
$sin^(^-^1^)(0.7)$
Al3dium:
Compile Error! Click the
reaction for details. (You may edit your message)
asin(0.7) ~= 44.427...
yeah, see? it's closer to 44
so you end up with 76
or you could keep the decimals and write the "true" angle
@upper karma just use the inverse. Which is csc
nah, it should be 44
this is a bad approximation
it's closer to 44, I should've jotted it down as 44
oh, well ๐
This is the figure, made in Geogebra
Omg
๐คทโโ๏ธ
Wow
I dont really know who is right/wrong
Should we just post it as a question. And see if anyone made a wrong assumption?
No clue. The figure doesn't lie, unless it's indefinite
Sounds good ๐
#help-1 ?
Should we just post it as a question. And see if anyone made a wrong assumption?
@upper karma do you want to?
#help-1 ?
@night karma lets wait for him to accede
go for it
hmmm
Les goo
@upper karma you could post yours in #help-1 and @night karma yours as well with all the context
(Sorry for the tag)
Still here, so no worries
@wanton lake whats your problem?
i just cant figure it out ๐ญ sorry
ahh ok
yes
the polygon angle sum theorem right?
Yes
yes i understand that
So
i did a few question like this before hand and got them correct as well
it mainly the (3x+15) that is stuffing me up a bit
From the theorem you should have gotten that the total sum of all the angles on a hexagon is ....?
180(n-2) right
Where n is the amount of sides
But
what he said
Yes but you arent him
Ok
I like geometry
So you both want to learn it
I already learned this
Lol
So dont answer
Ok sorry
I want him to do so
Ok
Yes
Iโll just watch silently
:)
ye i did 180(6-2) which = 720 i believe
Yes
And that gives us the total sum of all the angles on a hexagon
So
How can we make an equation, which contains/mentions the sum of all the angles?
How the equation should be?
well, im not sure it is correct. But normally/before i added up all the angles which i could get (100+140+90+120+120 = 570) and subtract it from the total sum of all angles on the hexagon
well, im not sure it is correct. But normally/before i added up all the angles which i could get (100+140+90+120+120 = 570) and subtract it from the total sum of all angles on the hexagon
@wanton lake and yes that its what you have to do, but with the hexagon
But this time
You know the total sum
And you are missing one part of one angle
yes
So
The equation generalised is:
a+b+c+d+e+f= total sum of all the angles.
Where from a to f are the angles
So apply that equation, to our problem
Hey? @wanton lake
ok
Ill wait
@wanton lake
(UPDATE: this is incorrect)
Wait
Thank you for stealing it
And ruining it
You just fucked up the learning process @upper karma
let my brain do it for a sec
did dspider posted the solutions?
Yes
the answer in the math book i am meant to get is 45
@upper karma we dont give away answers, we help them get to the answer themselves
am I in trouble?
no
But its really rude
^
unless u put it in spoiler than it's fine ig
so it would be (3x +1 5) where x = 150?
ok
so
100+140+90+120+120 = 570
720 - 570 =150
so it would be (3x + 15) where x = 150?
yep
So
and how i get x?
i believe this is the question https://cdn.discordapp.com/attachments/326138757474680852/704105253804703834/unknown.png
The equation generalised is:
a+b+c+d+e+f= total sum of all the angles.
Where from a to f are the angles
@upper karma
@high zephyr yes
@wanton lake please use the equation up there
Apply it to the problem
ok
Dont be scared of the x
100+140+90+120+120+(3x+15)?
yep
Its pretty straight forward now
indeed, just gotta find x
Lmk if you still need help
Yep
@upper karma also your method is completely wrong lol
how do i get x? ๐
$3x+15=150$
nighty:
ahhhh
Yes
u want to make x the subject here
That is the simplified form
so x = 45?
@upper karma u're supposed to subtract all other angles that is obvious, not angle (3x+15)
which leaves u with the expression for 6th angle
nah i dont think i missed any summing process
๐
dabs in needs a bit more help
i think i gpt it thx
Didnt got it
It doesnt matter
Look
Did you got the the (x+100) part
In which you need to apply a theorem
yep
me?
Yeah i was asking you
ok so what is it?
I mean, did you managed to solve the problem?
i think i gpt it thx
no....
yep, 2 angles that add up to 90 degrees?
Add up to 180*
mb
A straight line will have always 180
So yeah
supplmentary angles
True
supplementary angles add up to 180
They are called complementary as well i think
ok ok
Anyways, if you have one angle as (x+100) and the other one you dont know it, but you know that they add up to 180. The equation is...
give me a sec
Ok
ahhh im not to sure sorry
Its okay
Ill give you the general equation
a+b=180
Try to apply it, if you still dont know, lmk
oh, mb dat equation
yeah thats the supplementary theorem
lets say 'a' will be (x+100)
yes
And b the missing one
yep
The equation is ...
(x+100) + b = 180
Yes
So
We need b to apply the polygon sum-angles theorem
Like we did before
So b is
$b=180-(x+100)$
Al3dium:
$b=-x+80$
Al3dium:
yep
indeed
And applying the theorem of before
What equation do we get?
The one we did on the last problem
Called the polygon sum-angles theorem
What equation do we get?
.
ahh mb
... and...?
What does an equation need
(-x + 80) = b ?
$a + x = z$ IS an equation.
Al3dium:
$a + x$ IS an expression
Al3dium:
kk
Do you see the difference now?
i do
90+120+ (-x + 80) + (2x + 55)
Whats missing here then?
the equals sign
90+120+ (-x + 80) + (2x + 55) = 360?
YES
yay
hmm, could you help me a bit with that?
Yep
So we see that the parethesis are summing
And they are not being multiplied or anything else
yep
Al3dium:
Go on yourself now
occupied?
Yeah
ok
sorry Denton
Dont be sorry
so does x = 15?
ok ok
it does? nice
I didnt saw that the -x+2x = x
So yeah
You are done
@little osprey now it is free
:)
Ah thanks
y=3.497sin(0.5250(x+1.505))+13.95, C=-(1.505)-1.505
Would
C=1.505 or -1.505
because in the orignal equation it is represented as A*sin(B(x-c))+D
I got very confused tbh
AHHHH
x+1.505=x--1.505
Wait why am I so blind
hmm so -
but you said if comparing equation with original one
So then
why is
y=A*sin(Bx+c)+D a thiing
what i did just then is i compared the two eqns
i didnt bother looking at the other values
oh
im not too sure but the eqn is for determining transformations for a sine wave
for me im familiar with y=asin(nx-h)+k instead
gtg now
ah no worries
thanks for the help
I got confused at something that was completely trivial
ah alrighty
y all quick question ples
how come this circle of a wave function is not 2pi
normally half a circle is pi but here it is half pi
how come is that
what why
like shouldnt every circle be 2pi?
it s weird cos the question is calculate the length of the piece above y=2. what they do is calculate the radian of the area between t=0 and C
then they do that times 2. then pi minus then
do u get what i mean
so basically pi - the two lengths between y=0 and y=2
do u get that?
this way they get the length of the piece above y=2
my question is shouldnt they do 0.5pi - the two length, since the top half of the circle is 0.5pi and not pi?
the length of the piece above y=2
arc length or the chord
to be honest the parametric equations don't really matter that much
you could do 4cos42069t - 1 and 4sin42069t and it would still give a circle
treat it like a regular circle
CM is 4, and CD is 2
so you can find the angle
yeah i guess. that s how i accepted the answer lol. It s nothing like a circle but treat it like one
yeah i have the angle
but isnt it weird they do pi minus the two radians instead 0.5pi?
no it's not weird
like what is have that circle. is it pi or 0.5pi
because you're dealing with an actual circle, not the equation
ah ok
can i ask u about the third step in this question?
in the third step they have the length/rad of the up piece above y=2. That is (2/3)pi. to calculate the length of that piece, they do (2/3)pi * 4
so they basically calculate the perimetr of that piece
using 2pi*r
but isnt the length of that piece just (2/3)pi?
you mean to t=3pi/4?
(2/3)pi is the length of that and 4 is the radius
i dont know what that means sorry, the question is calculate the length of the piece of path/orbi taht sabove y2
have you found the angle CME?
then you can just use arc length = radius * angle
i don't think i'm allowed to help you out on your quiz
how come
read #โhow-to-get-help
so is arc length the rad of an angle or is it the circumference of a piece of a circle
judging by what the do it s the latter
i think
length of a piece of the circumference
a piece of a circumference is called an arc
handy lol
i thought they were the same
an arc and a rad of the same piece
thanks Conan!
does x = 63?
Yes
i feel smarter already XD
@solid swan I tried but failed.
i also tried but failed
yes
ooo nice
im actually getting dem correct for once
not to sure but i think this one is 140 correct?
a streak of 3
now my luck runs out probs XD
is this one 93?
@solid swan soz for ping but u r smart
what
to do this i'd draw a line through c parallel to AB and DE
then you can split it up into 37 + (180 - 124)
yes i did that
Won't it be 180-93?
i got 93 too
yay
dis one is new, since i dont understadn what it means or how to do it
how do i prove that they are the same?
the questions are on the left
im tryna figure dem out
just having tough tiem getting it a bit
oh also idk if dis helps but
Yes
Since they've marked it in the figure
With those dashes (sorry for not using appropriate mathematical terms here..)
so, if u dont mind me being dumb
wht would be the answers to the 3 questions?
Angle ACB = Angle DCE
DE will be 6
If you prove 1st point you can deduce the second point automatically
Since the triangles are "Congruent" they will be having same measurements
ahh thx
I hope you might be having an answer sheet to cross verify it
i dont, these are just from a bunch of random stuff online
so waht would the answer for question 2 be?
Oh, okay.
Errr since those triangles are congruent , which you will be proving in point #1,
You can say that AB = DE
This inturn deduces that DE = 6
May i know which grade math are you trying to solve?
year 10 i am in!
Oh, okay...
No, nothings wrong, all cool. It's just that i'm trying to help without knowing much about the question, so was scared if i might misguide you :p
So was verifying things
Do you know why those angles of the triangle can be proved equal? (Angle C)?
no, idk. not too good at math sorry
Okay so, using Vertical Opposite Angles (VOA) you can provr that they are equal
ok
ill move on to another thing i having problem with
would i use the same strat here?
yep got it
your pretty helpful
i think i got a test on dis in 1 and a bit weeks
goota study
Since AC is common it will be equal in both triangles
Paralle sides WILL be equal in a parallelogram
Hence 3 sides are equal
And the next point can be deduced using the congruence proved
Hold up lemme write it down
kk
u r helpful X)
not to rush u but u there? @untold flare
how do i find x and y?
I'll tell you in some time, eatin breakfast :x
all g
@wanton lake is Angle ADC 90 degrees?
not sure, doesnt say
Angle ADC And FHE
ahhh cool thx!
no
I am not sure about the x and y problem you gave me.
But the above parallelogram problem for the second statement you can say ONCE the triangles are proved congruent which means the sides are equal, that means the Angles projected by those sides will always be equal
@vital sleet
it is quite literally plugging in numbers into a formula
do you know the volume of a cylinder with radius r, and height h?
then go review your lesson again
recheck notes/textbook and come back
thats not what this server is for
that is also against the rules .-.
<@&268886789983436800>

@white cradle I shifted him outside the server dw ๐
a point in the right direction is appreciated. ```
Calculate the area if H is 12cm and the base edge 8squareroot3
the surface area?
yeah
well, don't you have the area already? you just need to plug in $a = 8\sqrt{3}$ and $H = 12$
Ann:
what confuses me is $P=2*\frac{a^2\sqrt{3}}{4} + 3aH$
since theres already a sqrt3 there, not sure whether to write it again?
ddm4313:
$a = 8\sqrt{3}$
Ann:
$P = 2 \cdot \frac{ (8\sqrt{3})^2 \cdot \sqrt{3} }{4} + 3(8\sqrt{3})(12)$
Ann:
why would you write 8 and not 8sqrt(3) for a when a is not 8?
just wanst sure
you were overthinking it
alright, now i have $\frac{384\sqrt{3}}{4} + 3(8\sqrt{3})(12)$ unless i did something wrong
ddm4313:
you've got a lot of simplification to do there
yeah, ended up going too far and got a crazy number lol
how is this exactly called in english?
what
can someone help me ?
triangular prism?
yeah, but like this formula
formula for surface area of an equilateral triangular prism?
thanks
Hi can someone help me out with this, I know how to do these types of equations when the domain in radians but not sure with this one, thanks.
the domain for this question is in radians
I guess I'm just lost, my thought process was to input the 0, and 3 to find the endpoints but im not getting an answer for it
2pi is a full rotation
so 2pi * x (where x = 3) would be 3 full rotations
you'd end up right where you started
but since it's divided by 3...
y'all overthinking it...
i mean you can substitute ฮธ = 2ฯx/3 and then ฮธ will range over [0, 2ฯ] and your equation will be sin(ฮธ) = -sqrt(3)/2
if that makes it easier for you to comprehend
ye I have no idea why I just started overcomplicating it, I had 2pi = root 3/2 and i was having mental block
Thanks guys
sine of what equals "-โ3/2" ?
pi/3
no, sin(ฯ/3) = sqrt(3)/2, not -sqrt(3)/2
think unit circle
-pi/3
(which corresponds to -โ3/2)
@slate lagoon need to find x "fast"?
is this a test?
yes
we're not allowed to answer tests
oh ok
not sure if this is the right place to post, but i need to find the x, and im rly confused.
it just "happens" to be the exact same question that @slate lagoon asked 30 seconds before you?
its freaking thales lmao
its some elementary stuff
just remove the /3 and you skip 3 steps xD
I don't get it, he changed his name from "Person" to "Human"
and the "@" id's no longer match
@silent fulcrum#0341
the hell...?
@silent fulcrum#0341
I right click his name, choose "Mention" and it ends up pinging some other random dude
with a different avatar
and different id number
"human"
do they give you any angles?
nope
consider properties of parallel lines and similar triangles
https://gyazo.com/72294c104340487e903f850c4eb5d919 which answer is right? ignore the blue outline
is this a test?
did you give the problem another attempt after seeing my suggestion?
not going to blatantly give out answers
Im not sure what you said, because I don't understand english very well
is this a test?
@upper karma its exercise
which language? someone else might be able assist
Estonia
1 sec orientation of that was bad
okay
why is it 5?
BEcause it is logical answer
apply the properties of similar triangles and solve the resultant equation
LIke Y must be bigger than 4 and lower than 6.5 thats logic right?
if you want to find y, don't worry about the middle part involving x
LIke Y must be bigger than 4 and lower than 6.5 thats logic right?
where's that coming from?
calculate area of a quadrilateral prism which base is 36cm^2 & diagonal of side 10cm https://cdn.discordapp.com/attachments/501175742504239106/704251884621529169/Capture.PNG
not sure what to do here
what is P?
p is area
h = height, b = base
is that a translation?
yeah
do you have a diagram to go with it
looks like its supposed to be a square prism
which diagonal are they referring to?
d_bs sounds the most appropriate
given B = a^2 = 36cm^2
were you able to determine a?
what do you mean
in your question, what would be the side length of the square base?
36^2
i need to get height i believe to solve this
i'm leading up to that
please try to follow these instructions
solve: $ a^2 = 36cm^2$ for $a>0 \
a = \ ?$
ramonov:
B = a^2
B = 36
a^2 = 36
a = sqrt(36)
a = ?
6
so a = 6cm right?
yeah
and you are also given that d_bs =10cm right?
yep
now consider $\triangle NPP_1$ in your diagram and apply pythagoras to determine the height (H)
ramonov:
thanks, d_bs is the hypotenuse, yeah?
yes
16 for what?
nevermind, i got 4 as b
what's b?
height
that is incorrect. show your work.
$b=\sqrt{10^2-6^2}$
ddm4313:
am i wrong?
not sure why you introduced another variable b, when you could've just used h,
but that seems ok so far
2?
well yeah, 10^2-6^2 is 4^2 and then 2?
no how are you getting "10^2-6^2= 4^2"
didnt square it
$a^2 - b^2 \neq (a-b)^2$
ramonov:
ok i got 8 now
thats better
alright, so height is 8, now we just plug in the values if im correct
ddm4313:
what is "M" supposed to be?
you know a = 6
you know H = 8
you know the formula for the area of a square prism
yes, i know, im just not sure if its correct which is why im asking
plug the values in
in the context of those formulas M is supposed to be the sum of the areas of those rectangular faces
Area = 2a^2 + 4aH
$P = 2 * 36 + 192$
ddm4313:
that looks okay
yep
(include units when writing it on paper)
264 cm2
just as long as we're absolutely sure that "diagonal of side 10cm" means d_bs and not D
because then the resulting area would be incorrect (since the wrong diagonal was used)
yeah, it is d_bs
I had some free time
math checks out
but I don't understand something from yesterday
b = 180 - (x + 100)
b = -x + 80
how?
distributive property
@silent plank
um, how are you getting from the first line to the second line?
that isn't how distrubution works
That is just wrong...?
$b=180-x-100$
If you are looking for that, im out of context here.
Oh its an x lol
Al3dium:
you added an extra 180 for some reason
^
I don't get it
distributive property is with multiplication
not addition
But what the hell did you do from the 1st to the 2nd
-(x + 100) is the product of (-1) and (x+100)
wow that's even more fuked up then
180 isn't being multiplied to those parentheses
which is what those red arrows seem to suggest...
It should lead up to
$b=180-x-100$
Al3dium:
Bc the minus is acting as an inversion of signs or what Ramonov said, as a product of (-1)
would you agree that: $180 - (x + 100)$ \
is equivalent to: $-(x+100) + 180$?
ramonov:
yes
and how would you have simplified the latter
but how do you get rid of that parenthesis?
Bc the minus is acting as an inversion of signs or what Ramonov said, as a product of (-1)
.
ramonov:
if you want
Multiply -1 to x and to +100
but that 1 is ass, ugly, unnecessary so we don't write it
-(x+100) + 180 everything * (-1)
(x+100) - 180
so the parenthesis then?
how do you get rid of it?
What
Multiply -1 to x and to +100
.
distributive property
distributive property
distributive property
distributive property
Lmao
distributive property is called "the distributive property of multiplication over addition"
you're saying you're doing this with the "invisible" 1 there?
Multiply -1 to x and to +100
. intesifies
You can do either of both
Which are the same lol
ramonov:
b = 180 - (x + 100)
b = -(x+100) + 180 (reversed, same thing)
b = ...
get rid of the parenthesis how?
Bruh
i'm done
all my messages seem to be written with invisible ink
(-1) * (x+100) + 180
-x - 100 + 180
-x + 80
ok, yeah
b = -x + 80
I get it now
distributive property makes sense now
-(x+100) + 180
is the same thing as
(-1) * (x+100) + 180
and when you distribute it you end up with "-x-100+180", which is "-x+80"
I get it
good job
if the equation was $\csc(z) = \sqrt{2}$, would you be able to solve for $z$?
Ann:
one of these is a solution of the equation, the other is not, and you're missing infinitely many solutions anyway if you are to solve this on the whole number line.
in other words, no.
z = 5ฯ/4 does not satisfy csc(z) = sqrt(2).
oh wait
@high wren do you understand how to get "z" from "csc(z) = sqrt(2)"?
x = pi/4 and 3pi/4
z
dspider no
no?
you are not going to tell this person to blindly "arccsc both sides"
i was almost there with my explanation

@high wren yes, csc(z) = sqrt(2), if z is only considered on [0, 2ฯ], has solutions z = ฯ/4 and z = 3ฯ/4. so you've fixed your previous mishap.
and i hope it's not that big of a leap from that to saying that the solutions of csc(z) = sqrt(2) on the whole number line are given by z = ฯ/4 + 2ฯn and z = 3ฯ/4 + 2ฯn, where n ranges over the integers
does that make sense to you
ok
