#geometry-and-trigonometry
1 messages · Page 298 of 1
there isn't
but you pretty much have to assume

the only answer that would make sense here would be the arc measure
i know
Which I already mentioned
we don't know how long the hour hand is
so my answer should be right
there is no right answer to this
ann yes
Bruh your answer?
there is no right answer
You told him to ignore me
which will be independent on the diameter and radius
simple as that, there is no right answer
the only answer that would make sense here would be the arc measure
why cannot we express hour hand as some function of diameter tho
20.9375
@upper karma that wasnt right unless i had to round to whole numbers
we don't know how long the hour hand is!!!
What if they want radians
An angle
@arctic vortex how am i supposed to know what you're supposed to do
Yes we have established that
we don't know how long the hour hand is!!!
@dark sparrow 12 to 6 is 180 degrees
because we have nfi how long the hour hand is relative to everything else
who's to say whether the hour hand is 5 inches long or 4 inches long or 3 inches long?
do you even read what i'm saying
yes
WE DON'T KNOW THE LENGTH OF THE HOUR HAND
WE DON'T KNOW THE LENGTH OF THE HOUR HAND
because we have nfi how long the hour hand is relative to everything else
well yes, but i mean general form
it will involve arbitrary constant
we don't know how big it is
lmfao
...
there is no way it will involve a constant lol
my answer should be right
the question is if they want to round it to 21
@arctic vortex try 21?
aight yall clowns wont listen to me i get it
look
for all i know, the hour hand could be any length between 0 and 8 inches
YES BUT THERE'S NOWHERE TO WRITE THAT FACT
it's pointless to try to guess
aight yall clowns wont listen to me i get it
@dark sparrow Read the chat history.
spiral should email their teacher
Agree
and be done with this problem
i guess
@arctic vortex try 21?
@upper karma Did you keep units
this problem certainly does not deserve such hot discussion
@little osprey not sure what you mean by units
inches
no its wrong
Yeah
well no idea then
Email your teacher
send an email
LMAO
wow
you know that dj khaled song
smoothest segue in the west
Suffering from success
what happened
no
yeah, i want an update when you email your teacher
Actually, same
though
time doesnt go backwards
meaning that 12 and 6 are semi circles
doesn't make any sense
huh
and since there are 6 hours in 180 degrees
d x pi = circumference
doesn't make any sense
@upper karma What are you on
yeah
I mean
and you guys ssaid that it was wrong :(((
like what are you talking about
denton
it could be the case that they just want an answer of 150 degrees
but that doesn't make sense, since they mention the diameter
to summarize
it's one of the worst questions i've seen in a while
is this asking for arc length or sector
What do you think?
Bruh
or anything i should study more
..
You posted 2 problems and literally skipped them?
For this one, recall a circle theorem
whats the circle theorem
If inscribed angles of a circle intercept the same arc then they are congruent. This follows from the Inscribed Angle Theorem. 7. If two chords intersect within a circle, the product of the measures of the segments of one will be equal to the product of the measures of the segments of the other.
this one
no wait this is tangent
wait
help
nvm
i think i got it
how do i do this
nvm i got that
i am
but i dont know the formula to solve it
for the rachel one i just solved the area and divided by 6
and did 12pi = 18.85
and 6pi
3pi
pi
I think my notes are wrong. It says z-scores are the standardized scores for x values. Is that wrong or correct
I don't understand what it wants me to do.
I converted 325 degrees to 5.672320069 radians. However, I'm not sure what it wants me to do next.
Do I divide by pi? - (Express in terms of pi)
Do I insert 5.67 into the s, and 12ft into r, for O=S/R?
Any help would be appreciated.
don't round until the end, until then keep your values in terms of pi. (just use the expression that you entered in your calc before pressing =)
s is what you're trying to find
the central angle will be theta
and s = r * theta
could someone please explain how they got arctan(1/-1) to be 3pi/4? the answer i got was -pi/4, and it seems like they got the supplementary angle as an answer of the angle that i got?
and the range of arctan lies in the first and fourth quadrant, so that also confuses me
they're using improper notation / function
but why do they use the atan2 function here? is it because im dealing with complex numbers?
the arc functions have limited range
it apples to the terminal positions of real points too
you need something to account for things that are in quadrants 2 and 3
oh! so Q2, i add pi, and Q3, i subtract pi
am i right?
or
the complex number im dealing with is -1+i, which would lie in Q2
so it would make sense to add pi?
yes
technically you don't need to know about the existence of the actual atan2 function.
just know about properties of the arctan function, quadrants and how to perform the appropriate shifts
(so there's no need to memorise it verbatim)
yeah, i havent used the atan2 function for anything in a long time
but i get how it works :) tyy
Sorry, I didn't respond sooner. I am also working and we have been really busy today.
So, i take 5.672320069*12=68.06784083
How would I write this in terms of pi? Do I divide by pi?
(just use the expression that you entered in your calc before pressing =)
i.e. to convert 325° to radians I'm assuming you did:
$325 \times \frac{\pi}{180}$
ramonov:
I'm not sure what you are referring to sorry.
5.672320069 is 325 degrees converted to radians. then I multiplied by 12 (ft) to get 68.06784083.
I'm just not sure where I'm going wrong.
No my calculator did the conversion for me
and that although unsimplified will be the exact value of your angle in radians
oh...
in that case learn the conversion that pi = 180°
How do I simplify 68.06784083 more than it already is? Well I supposed it can be rounded. So 68.07.
the instructions are confusing as fk
Yes, they are lol
i mean you did round correctly to 2dp
I might need to get my teacher to clarify what it actually wants.
so i'm assuming they actually want you to keep stuff exact
so try not to rely on the calculator for certain calculations
keep everything exact
specifically the angle would be what I wrote above
and multiply that by 12 (ft) for arc length
$s = \frac{325 \times 12 }{180} \times \pi \text{(feet)}$
ramonov:
oh okay. I'll try that thank you so much
and use appropriate tools to simplify that fraction
(express it as an improper fraction because mixed numbers are crap)
great that worked thank you
The help channels are solely for help with math, so feel free to post your question. Asking whether you can ask a question or if anyone knows about some specific topic is unnecessary, so please try to avoid questions of that nature.
Hello quick question: When people calculate area, they say their final answer is in units squared. But isn't the squared portion of the unit not relevant once you reach a final answer? Like say you have a 5x5 square, why does it make sense to say the final answer is 25cm^2?
I would understand if they said it the area was 5 squared, but I feel like I'm missing something
???
but isn't the square portion of the unit not relevant once you reach a final answer
??
?
Like you wouldn't say the answer is 25^2
you would just say 25
But apparently you DO say 25^2 is the final answer
and thats why I'm confused
Uhh? For a 5cm side length square area, A=l² so A=5*5=5²=25 cm²
Its not the same 25² than 25cm² which is the correct form
why is the unit of measurement squared?
is it because 5cm*5cm = 25cm^2
i guess that makes sense
but using units in a formula is new to me so doesn't feel intuitive i guess
Yeah fair
Everything is right except the vertical shift
Remember the vertical shift is halfway between the maximum and minimum
Oh wait
Amplitude also needs fixing
What’s wrong with the amplitude
4-1=3
Ohh
Can you help with me with the vertical shift
4-1=3
@pure pivot
how did you get 1
4-1=3
Yes
For this graph isn’t there a phase shift
it's not a phase shift
it's a vertical shift
so instead of +2
you should have +1
you said D = 1
Ok I got that
D is the variable commonly used for vertical shift
Cause rn I’m 3cos(pi/4x)+1
Why is it -3
Ohh nvm
you get why it's -3?
cause we start at the minimum, reach the midline, then the max, then the midline, then back down to the minimum
that's the pattern for -cosine
👍
Lol
I’m supposed to find a sine and cosine function for the graph. Sorry that it’s sideways lol
,rotate
anyway the sine and cos are going to be the same, just slightly different argument, since one will be a pi/2 - x shift of the other one up to other shifts and transformations
It’s in degrees lol
I didn’t even start the 11th grade lol
I’ll take note
For the sine function
I had f(x)= 4 sin(x - 270*) - 3
,w sin(x + pi/2) = cos(x)
not sure why
but anyway
pi/2 = 90 degrees
same thing, just wolframalpha doesn't like it for some reason in here
hello
Lol
why would you immediately tag me
idk
👍
but why you even need shift of sine here
it is pure sine
graph depicts literally 4sin(x)-3
well, if you want shift you can shift by 2pi and get the same
Yeah
The question was « Determine 2 equations using the parent functions sinx and cosx »
I had an equation for cosine as well
But I think I’m being retarded again
question is badly worded ig
what does mean determine two equations
"equation" imply that they should be equal to something
For the curve, it wants me to find a sine equation and a cosine equation
Using parent functions
well for cosine one
parent function is cosine
is it obvious that it is also 4cos-3?
To me it wasn’t obvious. It was my 1st time working with Trig functions
I only guessed the equations based on the amplitude and the horizontal shift
wtf was that
Idk
Can you not @pallid sierra
that sine-cosine have amplitude 2
since they both lie in [-1, 1]
so that's why you need multiply by 4
Oh
👍
insane right
Lol I have to find the points

what
Use common sense, if csc(x)=1/sin(x) we'll look at when the denominator equals 0
@forest niche
Wdym I’m sorry my trig is horrible
Idk I’m stupid I guess ;-;
$\csc(t)=\frac{1}{\sin(t)}$ and we want to see where the denominator equals 0, which will give us the vertical asymptotes
Al𝟛dium:
Or better lets just find the domain
Isn’t the domain all real numbers
too late lmao
It’s ok I’ll figure it out
the domain is $\mathbb{R} \setminus {0}$
polynomial:
It’s whatever I’m gonna watch some more YouTube videos it’s not a big deal
Thanks for trying to help
...
Commander Vimes:
lmao
yes
see, it's equal to the conjugate of infinity
@upper karma with no respect at all if you're gonna deliberately spout misinformation please fuk off
Commander Vimes:
$\csc (x) = \frac{1}{\sin (t)}$
variable fk up
Wait what I didn’t even say anything
so as it was said it wail to exist when sine is zero
variable fk up
@silent plank it is plan!
Commander Vimes:
so look
it fails to exists and results in asymptote when sin is 0
because limit of 1/x as x -> 0 is inf
that means that for asymptotes you need sin(t)=0
when sine is zero
do you know it?
@forest niche
I’m genuinely lost rn
well what do you know about sine?
Idk sine=O/H? 😂
i expected at least 10 copswings on poly's last latex
that's better but not enough
Yea idk what you wanted
Opposite/Hypotenuse
Idk what else are you looking for
Oh
Sin = y cos= x?
Somebody said that trigonometry is more about circles than triangles
pretty shit illustration ngl
Commander Vimes:
Yea
so look, when sine will be zero then
It touches the x axis
or what is the value of angle?
Idk 
Cos?
hello im new to the server and was wondering if i can get any help for these kinda problems
channel is clearly occupied
When sin is 0 cos is 0 what am I missing
@calm shoal just break the vectors into components, You have 2 vectors, one of magnitude 353, and an amgle of 229.2, you need to get the x component and the y component, using the cos(a) = x and sin(a) = y
so it would be cos(229.2)=353?
have you reviewed what the component method is?
not really lol
@long shale what happens when one side of a triangle =0?
@next jackal are you asking, when your on the axis?
Ohh sorry, I mistook you for that@forest niche guy
ooo
you can solve for the angles at the origin, use some trig and youll get the componets, do the same for B then add components
Hi I have this problem I know how to find X but I also need to find the angle between A and B
Is it possible? anybody knows how can I get that?
@silver fable what have you tried
Its for programming purposes I tried to get the angle of OA and OB and subtract them but doesn't seem right
is OC is perpendicular on AB
Yes it's always perpendicular
so how can you use that fact?
Oh right I can make a right triangle with it!
So I can easily get the angle between OC and OA and then after I got that I multiply it by two and I get the angle that BOA makes, is that it?
Yeah I already solved for X it's basic pythagora but sometimes it gives me wrong answers when the arc is so small which I don't think is a problem with the math which brings me here for the second solution
Thanks
Hi I’m a little stuck on this problem! I’m not quite sure what I can do next and was wondering if I could get some help😅
@neon sun ?
The question is in the brackets. To put the expression in terms of a &b when a=sin(x/2) and b=cos(x/2). If you understand what I’m supposed to do, could you give me a hint as to what I should do next?
@neon sun if you know the formula for sin(2x) and cos(2x)
use the same formula, but do sin(x) and cos(x) instead
as if it were x/2 + x/2
and expand
I see. Thank you!
Could 2-cos^2x/sinx not be simplified to 1+1-cos^2x/sinx?
Like it makes sense in my head but apparently its not correct
From here i could turn 1-cos^2x to sin^2x
Which makes the whole expression simplified to 1+sinx
The textbook just says cscx + sinx which makes no sense to me
Which makes the whole expression simplified to 1+sinx
this seems to be the part where you made the error
wait also
could you tell me
which parts are actually in the fraction
is it 2-cos^2x/sinx or(2-cos^2x)/sinx
ok good, the error is where you went from (1+sin^2(x))/sinx to 1+sinx
can you tell me how you got that result?
wait hold up right my bad
would still be wrong but
but still though, that means (sinx)(sinx) right?
yes
A factor can cancel with denominator right?
can you be more specific
for x!=-3 but yeah
because you have the one here
can you show me how that applies in this case
Isn't every factor that is the same, has the ability to cancel? (3)(3)/3 = 3 for example
I can't think of a scenario where this doesn't apply
yeah its true but what you have is $\frac{1+\sin^2(x)}{\sin(x)}$
Sneaky:
which part are you factoring out of the numerator
sin^2x
Since it composes out of 2 sinx's
OH WAIT I see now that 1 prevents this from being simplified right?
$\frac{1}{\sin(x)}+\frac{\sin^2(x)}{\sin(x)}$?
Sneaky:
that gives you $\frac{1}{\sin(x)}+\sin(x)$
Sneaky:
Right I see now
I was about to make an analogy with (1+3^2)/3 for a second there and I caught myself
That clears it up thank you for pointing out the dumb mistake
no worries
👍
csc(x) + sin(x) yEet
How do I tell
circles are congruent if they have the radii of equal lengths
Oh ok then it’s not congruent because they would have to overlap
Ababababababba
Abababa
Abababababa
can anyone help me with some geometry problems ??
@arctic vortex go with them
The help channels are solely for help with math, so feel free to post your question. Asking whether you can ask a question or if anyone knows about some specific topic is unnecessary, so please try to avoid questions of that nature.
First, is it a test?
nope
Ok good
it is homework assignment
Let me see
my test is on august 8th
its the final exam
i have 15 problems but i only need help with like 6
Okay yes it is a
You have angles and a circle. I would recommend going through the facts you have about angles and circles, and seeing what they tell you. You might not know which facts will be helpful, but if you go through them you'll have more info than before
okay
i will do that
in the mean time can u check something else @teal stag ?
im confused on inscribed angle and central angle
The boxes you have look good. "central" means it's at the center of the circle (which is A). "inscribed" means it's drawn on the circle itself (which D is)
good thinking!
thank you :)
for this one the answer i got was 2/9 = 169pi
how do i make it so that its one of the answer choices
@teal stag
2/9=169pi is an equation, and I don't think that's what you meant to write
yes
Both "2/9" and "169pi" are important values here, but what is the area (in terms of pi)?
169* * 3.14?
Let me rephrase. "2/9 = 169pi" is obviously false because the left side is less than 1 and the right side is over 400. What did you mean to write?
That's an equation which is false
yes
The area of the section of the garden isn't the equation "2/9 = 169pi", it's the number: "???"
Let's break this down. What's the area of the whole circle?
I think this is something you already figured out. I just want to highlight the steps of the process.
That's approximately the area of the whole circle. If you just say "the area" you could confuse yourself as to when you'
re talking about the area of the whole circle and when you're talking about the area of the sector
The area of the whole circle is exactly $169\pi,\mathrm{ft}^2$
dirib:
yeah im talking about the sector area
The sector area is much less than 169pi
yes
That's why I'm emphasizing the distinction
Now, what fraction of the whole circle is the sector/section of the garden? (this is also something you figured out)
so its 2/9 of 169pi
An area of the sector can be found by using the formula theta/360 ^ Pi * R²
right. And when you have a fraction "of" a number, what do you do.
multiply
Right
117
so it's not "2/9=169pi"
.98
it's "(2/9)*169pi"
You already had the pieces. I just helped you put them together
yes thank you :))
I have to go now, but if you have more questions, others here can likely help
I was happy to help, though
okay
same i was happy for u to help me :)
ok i will post this one is it 12 ??
because 2 * 3x-2 = 5x
x=4
and then 10 + 2 = 12
oh
@arctic vortex are you asking for help with this question?
yeah
although id write it as 2*(3x-2) instead
when you write it as 2*3x-2, it looks like you mean 6x-2 rather than 6x-4
yeah true
wait would tihsb e 50
this be *
because 92 is a vertical angle
@olive solar
are you certain angle RSQ = angle SQT and not RTQ?
look at the arcs formed by each angle
yes
how did you decide on 70?
180-110
so the portion of the segment SR that is also within C is a chord, yes?
yea
and QS seems to be tangent to the circle
so here you would be using the tangent chord angle thm
ohh
the question doesnt really confirm whether that's a tangent though so 
i solved that one @olive solar can u help with tihs?
Is this right?
@arctic vortex do you know how to find the angle of an internal angle given the measure of its arc
@livid sequoia do you know the classification of a rhombus
can c be considered to have 4 congruent
yep
thank u
you are able to find angle C given everything in the diagram@arctic vortex
once you have angle C and angle A, angle B can be found based off the properties of a triangle
64?
howd you get 64?
remember, C is an inscribed angle
i could tell you the solution but i won't
look at how to get the measure of an inscribed angle from the arc it forms
do you have a textbook?
id recommend that you go through either that or get some proficiency with google
you could search "inscribed angle theorem" and youll get what you need here
how can I retrieve the general formula of a transformation in the complex plane by having the matrix form?
I'm used to doing it the other way around
even better - I have the general expression in terms of x and y
I think I'll plug in i in the y value?
wym matrix form
well
I have general expression f(x, y) of a plane transform
and i want it to be f(z) = cz + d
and I forgot how to do it 😐
Um, can you figure out what the transformations are that get you from start to finish?
(agrees with ann)
ok, here's the exercise
can you maybe be more specific
so I know f is a translation after a transformation
with this matrix form (right?)
I suppose it is an homotety
because the ratio is not 1
and it's given that f(x, y) is a transformation, if that helps...?
uh
well i guess you could write $f(x,y) = \mat{2\3} + \mat{\sqrt{15}/10 & -\sqrt{10}/10 \ \sqrt{10}/10 & \sqrt{15}/10} \mat{x \ y}$
Ann:
for the actual "matrix form" of the function
(yes, that's what I did, but it's not terribly useful)
[a, y] * (2 x 2 rotation matrix) + (x_0, y_0) = (xfinal, yfinal) ? 🙂
and that makes it more clear that this actually CAN be expressed as an affine map on C
sorry I got the order wrong
$f(z) = 2+3i + \frac{1}{10}(\sqrt{15} + \sqrt{10}i)z$
Ann:
multiplication by $a+bi$ considered as a linear map on $\bR^2$ has the matrix $$\mat{a & -b \ b & a}$$
Ann:
oooh
actually pretty straightforward
if I want to calculate the image of any vectorial eq.
in this case, something like (0,0) + (a, b)
is it okay to plug in z = a + bi in the f(z)?
could anyone help me with this? Im not sure where to start
What have you tried
Well its a proof so all I've really done is write the givens lol
tried looking online for some help
didn't really know what to look for
Is this a question from your teacher or
ye
Nothing unfortunately, Im asking around with my friends but none seem to remember
Have you used any circle theorems
I'll go check some more out
Hint: right angle
Join AP and BQ
ah
Anything?
sorry nothing's clicking for now, but thanks though!
Lol
Well you could stay here
and I could try and guide you to the right direction
that'd be great lol
Well what happens when a radius is drawn to a tangent point
I want to help, but you have to put some effort in :/
Yeah, sorry man, I not too good at this as you can see
I remember something about it being perpendicular or something like that
Ok, correct, but remember AB is also tangent
Sorry for delayed answers Im just looking at definitions at my other screen to piece things together
No worries dude take your time, I understand
PAM and QBM will form right angles as well?
now that I wouldn't have gotten
Because they are tangent
Do you understand the reasoning
a bit but could you explain why it being tangent forms right angles
The proof?
actually
nah its ok
I think I can handle the rest with my friends seeing as theyre awake now
thanks for all your help bro
I really appreciate it
No worries dude, sorry I couldnt explain it well enough
nah its alright Im just not good at these things
nah its alright Im just not good at these things
@PrivateFishy#2029
What's the problem??
Could i try to help
do you know what a sine or cosine is?
so with part b, would y be tan(50)=x/y or cos(50)=y/12?
ya
or can it be both
okay yeah i just wanted to know if one of them was more
right i guess
i know it’s easier with cos so i’ll just put that
👍
I don’t think you proved triangle AEC=DEB. If I remember correctly from my geom, that should be your last statement if you are trying to prove it.
ooh yeah you’re right
Pretty sure that's a typo
yeah i meant to put AEC congruent to DEB
oh yeah i also need help with a trig problem
hold on
for c would i be right in saying i can’t use the tangent ratio?
and sorry for the bad hand writing, i could clarify if needed
oh wait let me clarify the question
the question says would you be able to use the tangent ratio to solve part a-b
so if you use tangent to solve a you can get x?
wouldn’t that give you tan(50)=x/y?
but when i put it into my calculator it gives me x=1.19175359y
so wouldn’t you need at least one value before solving with tangent?
if you use tangent you're gonna have to use cosine and sine
but its still possible
oh okay
i just think the question is asking whether we can use tangent for both before using anything
do you have the question?
yeah i’m just gonna ask my teacher
“Are you able to solve a or b with the given info using tangent as opposed to how you actually did it? That’s what the other student is claiming.”
i think i’d be correct right?
cause you can only use tangent when you solve one of them with sine or cosine
Would that be considered an inscribed angle or no? Bc if so then woudlnt 1=21.5?
Or would I do like 92-43=(1)
neither
I honestly don’t know what I do I thought I was an inscribed
1 isn't at the circumference
look up something like
outside angle theorem for circles
which can be derived from inscribed angle theorems
yes
Thanks also I need help with this question could you like tell me with theorem or what rule I use so I can look it up
cyclic quadrilaterals and alternate segment theorem
Ok thank you
whoops i mean inscribed angle theorem / central angles instead of cyclic quad
yes
Any idea to solve acos(x)+bsin(x)=c
Looking for x?
I got this question as homework a couple days ago and I've been confused since. I got no clue where to start.
What's the general formula for the volume of a prism?
Its just A x H
Ye
How would you go on calculating the volume
You have both A and H in this case
I thought the radii were given too
That's the correct answer
It has to be the right answer
Because that's the only volume you are able to calculate
yeah
ok so im taking my geometry finals soon and i want to ask if there are any tips u guys wanna give me
don't forget about the ambiguous case with sine
Good tip
hey can someone give me a little hint.
ABCD is a parallelogram and I is midpoint of line BC
Line HD is perpendicular to AI with H a point of AI
Show that CD = CH
here's the sketch i have drawn:
idk what should i use, but i think it'll be about angles. i tried to find similar triangles but couldn't.
maybe proving HCD is isoceles
shall we chase angles or shall we not?
help
@livid sequoia What have you tried
Do you know what the pythagorean theorem is
yea
and why did you subtract?
apply pythagoras two times
I said why did you subtract because you didnt square them
you must square sqrt(2) and 1 and then substract
yes but remember
yes
add a last step
thank u
no worries
@charred zephyr I'll take a look at your problem layer, Imma @ you if I find something interesting
Hell yeah HoboSas
Ok that probably took too much time
||Let G be the midpoint of side AD||
||For Thales theorem we have that DM=MH (you can also check this noticing that triangles DMG and DHA are similar and their "ratio of similarity" is 1/2)||
||Consider now triangles DMC and CMH, they are congruent for SAS (DM=MH, right angle and a shared side). In particular CD=CH.||
@charred zephyr
how would i find the area of this triangle?
@lusty quest Heron's formula
ahh ok thanks
Have you heard of it?
definite integrals
yes, i just havent done this in a while
You can measure area of planar object by weighing it on scales: cut it out of some tin (to scale, for example in cm), weigh 1 square cm piece of tin, then weigh the triangle, and you get numerical value for the area from weight
