#geometry-and-trigonometry

1 messages · Page 365 of 1

wanton portal
#

What is the actual answer?

#

This is all that I have solved it with

#

Then taking its squareroot

wheat belfry
#

Help pls, with the process

lone copper
wheat belfry
#

ye

#

heeeeelp

#

Just one

#

is better if you can all

wanton portal
#

Hey, I have made a video on a "Secret Proof for Pythagoras Theorem". I think you all will throughly enjoy it. Should I share it here?

#

Pythagoras Theorem is the most popular theorem that math has to offer. But most can not appreciate it's beauty, subtleness, and wide spread usage. This video will help you prove why Pythagoras Theorem is true in the best way possible. Weekly Newsletter: https://brainspoof.mailchimpsites.com/

▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
References
Elements of G...

▶ Play video
upper karma
#

sin^2x = 2sinxcosx
is this correct?

humble pulsar
#

$\sin(2x)=2\sin(x)\cos(x)$

somber coyoteBOT
upper karma
humble pulsar
#

what?

upper karma
#

sinx . cosx = m
what's [sinx - conx]
the absolute value
I hope that's what it's called in eng
sinx . cosx = m
what's [sinx - conx](absolute value)

humble pulsar
#

?????

upper karma
#

this is the question

#

sinx . cosx = m
what's [sinx - conx](absolute value)

humble pulsar
#

I have no clue what you just typed

upper karma
#

still?

humble pulsar
#

nope

upper karma
#

what's wrong with it

somber coyoteBOT
#

peaceGiant

agile geyser
#

help me with something in geometry guys it is posted in question 3

#

please please

#

@wanton portal

timber tapir
#

can someone explain to me how tan(1) = is pi/2

#

like if tan = sinx/cosx

#

so then sin1/cos1, (pi/2)/0

#

undefined

dark sparrow
#

what are you talking about???

#

sin(1) isn't pi/2 and cos(1) isn't 0...

#

and tan(1) isn't pi/2

#

,calc tan(1)

somber coyoteBOT
#

Result:

1.5574077246549
dark sparrow
#

,calc pi/2

somber coyoteBOT
#

Result:

1.5707963267949
dark sparrow
#

it's just coincidence that these values are somewhat similar

#

@timber tapir

timber tapir
#

bruh am i dumb

#

sin(1) = pi/2

#

right

#

or like

dark sparrow
#

no.

timber tapir
#

is that not how that works or what

dark sparrow
#

it's sin(pi/2) = 1

timber tapir
#

oh ok

dark sparrow
#

the input of sin, cos, tan, etc. is the angle

timber tapir
#

so how am i supposed to find the value of sin(1)

dark sparrow
#

you aren't

#

not by hand anyway

timber tapir
#

yes i am

dark sparrow
#

what?

timber tapir
#

practice exam has me finding value of arctan

#

of (1)

dark sparrow
#

arctan(1) is way different

timber tapir
#

how so

dark sparrow
#

well for starters this is an inverse trig function

#

arctan(1) is the solution of tan(θ) = 1

#

(subject to some restrictions on θ to make sure there's no ambiguity)

timber tapir
#

oh i was thinking it was 1/tan(1)

#

lol im dumb

dark sparrow
#

no it isn't

#

arctan is not cot

timber tapir
#

just learned the unit circle 2 weeks ago

#

halfway thru calc 1

#

lol

#

but that's the least of my worries

wintry tundra
dark sparrow
#

no???

#

what are you talking about

wintry tundra
#

Yeah they are almost the same

#

They both have a t in them

dark sparrow
#

.................

#

not funny.

wintry tundra
#

Ur just biased

dark sparrow
#

are you being serious rn

#

i sure hope not

wintry tundra
#

I'm being 100% /srs

weary drift
wintry tundra
#

Exactly the same

weary drift
#

@wintry tundra pls don't shitpost here

wintry tundra
dark sparrow
clever fable
#

hey, I was just wondering, why is there two thetas, in the triangle here

#

shouldn't it be pi/2 - theta, (for the point M)

clever fable
#

(or is it just a mistake they made?)

signal swallow
#

your angle is always taken from the x axis, not the y

clever fable
#

can you expand on that please??

#

so is the diagram wrong then?

signal swallow
#

pi/2 is the y axis, so if you did pi/2-theta, you'd be taking an angle from the y axis

#

angles are taken from the x axis

opaque ibex
#

hey, seems like c and d inversely proportional in the f(x)= a.cos(cx + d) + b function but i don't get why

dark sparrow
#

what do you mean?

#

inversely proportional under what circumstances?

opaque ibex
#

In the graph, the coefficient c is setting the amplitude and d is setting the translation, but the translations of d are affected by the coefficient c in the coordinate system. In a inversed proportial-->

#

cos(2x + 1) + 6 and cos(x + 1)

#

cos(2x + 2) + 6 and cos(x + 2)

#

cos(2x + 1) to cos(2x + 2) delayed 1/2 unit but why not 1 unit is what i'm asking

pure cape
#

tbh, d is not the translation in the x axis

#

the translation in the x-axis is d/c

#

which way?, that depends on the sign

#

and c and d are not inversely proportional to each other

pure cape
opaque ibex
#

oh that explains

#

thank you

pure cape
#

what have you tried?

#

you have used the wrong sides

#

you have to understand that the general volume formula for prisms is B*H where B represents the area of the base and H represents the height of prism extending from the base

#

now from that formula, we achieve the formula bhl/2 for triangular prism

#

where b is one of the side of the triangle base, h is the length of the altitude to that side aka the height of the triangle, and l is the length from the base

#

lemme just name some stuff first so its not vaguely describe

#

alright, so in this case, what you need is the area of the triangle

#

which is basically AB*BC/2, since this is a right triangle at B

#

well, one could argue that you can draw an altitude from B to AC

#

and yes, i agree, you can, but why make it hard when you have the easy way

#

so you just need BC, which is pretty straight-foward to find

#

so to conclude:
Base=AB (or BC)
Height=BC (or AB)
Length=BB'

opaque ibex
#

so finding BC using pythagoras theorem was a coincidence then I guess.

abstract cosmos
#

That's truee

pure cape
#

i never said it was false, and i have explained where and what the formula means

#

again i have listed out what should do

#

it seems like you are not reading any of my message

opaque ibex
#

how to find BC?

pure cape
#

pythagorean

#

or if you want to do it the hard way and find the altitude from B to AC then also pythag

opaque ibex
#

yeah that works but it says nothing about a right angle or B to AC will be a median

pure cape
#

?

#

its not and why does that matter

opaque ibex
#

so if it's not 90 degrees we can not use pythagoras

pure cape
#

yes

opaque ibex
#

so whats BC

pure cape
#

if the information right triangular prism is not given then not enough information is given

#

use pythag?

#

oh i just realised i read the question wrong

#

yeah, then not enough information is given then, we would need at least an angle or another side

void agate
#

How to find vector PQ in terms of vector AD and vector AB

#

i have found :

#

5/7 AD - 4/5 AB

#

Is this correct?

primal kite
#

someone help

#

;-;

oblique hatch
# primal kite

So, your angle is theta, so that's the angle you'll be working off for each triangle. For example, on Triangle 1, opposite theta is 8 and adjacent is 6. What angle uses Opposite and Adjacent?

sand jolt
#

I'm having some trouble here with this first problem. I'm not the best at logic stuff like this. (Also the Coliseum window is just a room with a long window on one end of it.)

#

I have a graph too if it helps any.

#

Like you're not standing outside since you're at y<0, you're above ground since z>0 and you're just standing 2 meters to the right for the x. Right?

humble pulsar
#

It's a right triangle, so one side is the diameter

chrome trout
#

Hey ya'll 🙂

#

I'm in a trig class, I like trig, im happy to do the work. I have been struggling understanding Trig concepts and I think it is because it is all lacking human interaction. Anyone care to review some trig topics with me? I have a test in 10 days = /

void moat
#

also, do you know how to solve trigonometric proofs

#

and finally trig word problems

#

know all your double angle formulas, and trig identities

#

cirumscribed means that the triangle is in the circle

pale onyx
pure cape
#

how what?

#

the similarity?

#

or the ratio?

neat stag
#

are the designs made on table or cloth? but the cloth is hexagonal

lone copper
#

qn is not clear enough but it seems like the design is the part on the table that the hexagon doesn’t cover

neat stag
lone copper
#

i think no that’s why the hexagon is there to cover the rest of the table

neat stag
#

dude this questionslightlyembarrassed

lone copper
#

this qn is very unclear

neat stag
#

i Haven't seen such table tbh

hoary rover
#

help

hollow raft
#

@hoary rover what in the fuck

#

What math are you in?

#

Like is this a high school geo?

winter pumice
# hoary rover

Wow, I'm not familiar with the [ABCD] notation. Is that an area or perimeter?

nocturne remnant
#

Area

#

Probably

hoary rover
#

area

winter pumice
#

ok

nocturne remnant
#

Just assume ABCD is a square opencry

hoary rover
#

why?

#

bruh

winter pumice
#

there's so much here it's like intending to throw students off

#

it's an exercise in willpower

#

idk actually maybe they really want you to remember all the notation

stray schooner
void agate
#

Hello, could someone help me solve this problem:
In quadrilateral ABCD, P and Q, are the midpoints of opposite sides AB and CD. The point M is the midpoint of BCD and N is the midpoint of PQ. Prove that the points A M and N lie on the same line.

#

I think it should look something like this:

nocturne remnant
#

C does not always have to lie on the line ANM

#

but in any case, ||Menelaus’ on BPQ should work||

shut finch
#

Im late to the party ik

cerulean nest
#

Great app, I use it all the time

sand jolt
silent plank
#

the work is messy but you'd need to determine the area of the base triangle (which is implied to be a right triangle)

#

which can be achieved by first determining the length of the unmarked leg using pythagoras

shut finch
#

what d you find confusing i will try and help

shut finch
#

OK you have to work out the sides of the triangle and use them in your formula

silent plank
#

note that 10ft is the length of the hypotenuse and is NOT the height of the triangle

shut finch
#

Exactly Romanov

silent plank
#

the work is messy but you'd need to determine the area of the base triangle (which is implied to be a right triangle)
which can be achieved by first determining the length of the unmarked leg using pythagoras

shut finch
#

No 8 is the height

neat stag
#

Four circles are drawn, with the centre on the verticies of square... Each circle touches the boundaries of two other circles out of four.
How are their areas equal??

silent plank
#

doesn't really matter than much

#

if you consider 6 to be your base, 8 will be the height

#

and vice versa (you can consider 8 to be the base and 6 to be the height)

shut finch
#

@upper karma try to think of it that way

silent plank
#

either way you'll have 1/2 * 6 * 8 or 1/2 * 8 * 6 which has the same value

#

(which is implied to be a right triangle)
which can be achieved by first determining the length of the unmarked leg using pythagoras

winter pumice
winter pumice
# dusky surge

Neat. So blue circles (every other) can vary in s/2 <= r_blue <= s/sqrt(2), as s/2 <= r_red <= s(1-1/sqrt(2)) ?

#

Doesn't that disprove the premise that they are all the same?

#

*same area

dusky surge
#

Yea I guess, since the radius of the circles varies...

#

Varies from (√√2)/2 to 2-(√√2)/2

#

Although I just did (√√2)/2 to 1 as demonstration

#

And of course you can prove it algebraically

neat stag
#

can I make 4 circles, centred on verticies of a square and each touching the other two, which are not equal in radius and, hence, area?

#

so whats the justification or reason for these circles having equal area

dusky surge
#

See if this can help

winter pumice
# neat stag i mean can you put it in simple terms

They don't all have equal area. Please state the problem exactly as it was given to you. If you have, the claim that all circles have equal area isn't always true under the required conditions (that all circles are tangent to two circles).

#

however, circles in opposite corners do seem to be guaranteed to have equal area.
Area depends entirely on the radius (A=pi*r^2).

neat stag
dusky surge
neat stag
#

they reject that only opposite ones can be equal

#

and take the second one where all r equal

dusky surge
# dusky surge

From my example, I used square of side length 2, then the "shaded area" will be
2²-(r²+(2-r)²)π/2
Where r in a real number between 2^(¼)/2 and 2-(2^(¼)/2)

dusky surge
#

Since it's some fixed graph and not moving ones.

winter pumice
#

it's not animated I guess because there are two parameters...dumb

#

@dusky surge you know how to make the second slider animate?

#

does the side length need to be constant? that would be a shame

dusky surge
#

Haha I don't know how to make 2 slider animated

winter pumice
#

no, just the last one

#

I never wanted the first one animated

proven adder
#

yo can someone hop on call with me i got a problem solving arccsc(sec2pi/3)

winter pumice
#

ooh! me

dusky surge
#

Dunno lol, I don't really know how to use Desmos

winter pumice
storm portal
#

In 2D space, yes

#

In 3D space, not necessarily. It can be mapped onto itself. It depends on where the line is rotated about

molten delta
#

So we know that the formula for the circumference (the base of a cylinder is a circle, and the perimeter of a circle is the circumference) is (2)(pi)(r)

#

Yea?

#

Yes we can also use that formula as well

#

And since we are using pi = 3, let’s change the formula to (2)(3)(r),

#

So you got it?

#

Or…

#

Ok so

#

Right we are going to get there in a moment

#

So the formula in this case is C = (2)(3)(r)

#

C being the circumference

#

And since we’ve already been the circumference, which is 24, we plug it in

#

24 = (2)(3)(r)

#

Since the circumference is the perimeter of a circle

#

And a cylinder’s base is always a circle

#

Yep

#

24 = (2)(3)(r)

#

It’s a simple equation from there

#

Just solve for r

#

Yea for sure

#

It’s just we need to convert the d into r later on

#

So the formula now is C = (3)(d)

#

Yep

#

Then we just solve for d

#

Yep

#

Perfect

#

I mean we could use the process of elimination here

#

Or we can check mathematically

#

F would be 25/12

#

2.0833

#

Yep

#

Since we rounded down pi from before

#

So they rounded up the final answer

#

Hmm I mean that just depends on the question

#

If it asks you to round to the nearest tenth then that’s what you should do

#

I feel like the book your using shouldn’t have done that

#

It’ll likely be more specific in exams and tests

#

No problem have a good night/day

neat stag
neat stag
dusky surge
neat stag
dusky surge
#

We can.

dusky surge
#

Or for your case

#

14²-(r²+(14-r)²)π/2

#

Where r is the changing radius or one of the pair of circles.

winter pumice
neat stag
#

well i guess I'll have to stick to the radius being equal case

#

it makes it easy and i get the answer

#

and marks lol

dusky surge
#

Lol, I think that's what they want

mystic karma
#

so basically the answer should be 42 Cm^2

winter pumice
#

unless the radii are allowed to vary

#

but your picture and description pointing to the picture implied they weren't supposed to

mystic karma
winter pumice
#

yeah, I was just telling my boi @dusky surge about that

dusky surge
#

Kek

winter pumice
#

But I wasn't refering to a person

#

just the picture

#

was this your problem?

#

thought it was theirs

mystic karma
#

😂 you guys got confused a simple question with a complex one

winter pumice
#

@neat stag

mystic karma
#

but how do you solve the complex type ?

winter pumice
#

complex meaning....?

mystic karma
#

in which the radii may vary

dusky surge
#

You can scroll all the way up~

winter pumice
#

the complicated one?

mystic karma
mystic karma
neat stag
winter pumice
#

there are two pairs with radii that have one value, and two pairs with a complimentary value

#

the sum of the radii must equal the side length of the square

#

so you can just subtract half-times the area for both cases from the area of the square whose area is (2s)^2 (if you're going by how I put it in Desmos)

mystic karma
#

ok thanks

winter pumice
#

let $s$ be half the side length of a square and choose r such that $$r \ni [s(2-\sqrt{2}),s\sqrt{2}]$$

un-simplified:
$$A = (2s)^2 - \frac{1}{2}\pi r^2 - \frac{1}{2}\pi(2s-r)^2$$

somber coyoteBOT
#

Disorganized

winter pumice
#

$$A(s,r) = 4s^2 -2s\pi(r - s)$$

upper karma
#

sinx/1+cosx + 1/tan

#

the simplest form wanted

upper karma
somber coyoteBOT
#

Disorganized

mystic karma
winter pumice
upper karma
#

how

mystic karma
#

so basically multiply sinx/cosx+1 with cosx-1

upper karma
#

wait

winter pumice
#

@upper karma please confirm what the expression in the denominator is

upper karma
#

I don't get what you said

mystic karma
#

i also have a doubt lemme share it

#

2sec^2 theta - sec^4 theta - 2cos e * c ^ 2 * theta + cos e * c ^ 4 * theta = cot^4 theta - tan^4 i

winter pumice
#

is your expression

upper karma
#

yes

winter pumice
#

$\frac{\sin{x}}{1+\cos{x}} + \frac{1}{\tan{x}}$?

somber coyoteBOT
#

Disorganized

winter pumice
#

ox then

#

ok then

upper karma
#

they want me to make it the simpliest

mystic karma
winter pumice
#

just write $\tan{x}$ as $\frac{\sin{x}}{\cos{x}}$ to start

somber coyoteBOT
#

Disorganized

upper karma
#

yes I know that

#

then?

winter pumice
#

I think simplest form would have 1 term

#

so get common denominators

upper karma
#

did we do
1/tan > 1/sin/cos or cos/sin ?

winter pumice
#

(cosx)(sinx)/[(cosx)(1+cosx)] + (1+cosx)/[(cosx)(1+cosx)]

winter pumice
upper karma
#

I meant

#

I fixed it

winter pumice
#

so if it's on the bottom of 1, that is, 1/tanx, that's 1/(sinx/cosx) = cosx/sinx

upper karma
#

1/tan > 1/sin/cos or cos/sin ?

winter pumice
#

ohhhh

#

hang on I made a typo

#

lemme just pencil it

#

@upper karma

upper karma
#

wow

#

thanks

#

I'll try to do it myself

winter pumice
dusky surge
winter pumice
#

Are you sure you typed that as it was given to you?

mystic karma
mystic karma
winter pumice
#

and I know typos very well

#

maybe take a screenshot

#

or use LaTeX

mystic karma
winter pumice
#

it takes a lot of practice,

#

just take a screenshot

mystic karma
#

ok

#

i have the solution too but wasnt able to understand it

radiant girderBOT
dusky surge
#

Hmmm... Can it be shown like... A picture? All I can see is a downloadable file

mystic karma
#

how do i do that

dusky surge
#

Use the camera?

mystic karma
#

i was on my laptop

dusky surge
#

Ohhh

#

Alt-print screen

mystic karma
#

oh thats good

#

is this fine

dusky surge
#

Much better

#

I see, that's cosec

mystic karma
#

if you solve it on paper , pls give reasoning for the steps

#

yea

dusky surge
#

Lol the Google lens got cos(e*c)

mystic karma
#

yea XD

dusky surge
#

Okay, on my first thought
I think you can group
First 2 terms together and of course, the last 2 terms together

mystic karma
#

@dusky surge if you were bri'sh would you be known as crumpet

mystic karma
dusky surge
#

Like since they have a factor
sec²θ in common

mystic karma
mystic karma
#

wait lemme show you

#

this is the solution

#

but i lose understanding from step 3

upper karma
#

What did I do wrong?

mystic karma
#

wait

winter pumice
#

what

#

skipping steps, making mistakes

dusky surge
upper karma
dusky surge
#

I'll come back later

winter pumice
upper karma
#

Ok

winter pumice
#

also your notation for multiplying top and bottom by something, I've never seen that before. You followed through with it on the left but messed it up on the right in step 4. Maybe just write it out

#

"say what you mean"

#

pretend you are teaching someone else what you are doing

upper karma
#

uh

#

alright

mystic karma
#

this solution is also correct right ?

#

to swain's question

mystic karma
winter pumice
mystic karma
#

huh why

#

oh shit

#

i see sorry 😂

winter pumice
# mystic karma

they are separating the sec(x) and csc(x) parts and anticipating a polynomial perfect square trinomial form

#

both polys are of the form x^2 - 2x + 1

#

they were just missing the 1's

mystic karma
#

oh now i see

winter pumice
#

the 1's they appended will cancel

mystic karma
#

so basically of the form ax^2 + bx + c

winter pumice
#

more specific then that, but yeah

mystic karma
#

this was very helpful thanks

winter pumice
#

they were going for a perfect square trinomial

#

analogous to x^2 - 2x + 1 = (x - 1)^2

#

if you let x=t^2, you can see it still works

#

t^4 - 2(t^2) + 1 = (t^2 - 1)^2

mystic karma
#

oh

#

u r a genius or what]

winter pumice
#

you can also do it with trig function substitutions. They had x= [csc(theta)]^2 in the first one and x = [sec(theta)]^2 in the second

winter pumice
#

but I've been doing this for about 15 years longer

mystic karma
#

oh much appreciated man

obsidian marsh
#

Is this correct? It feels wrong for the area to go to infinity when the angle goes to zero.

quiet blade
#

Oh, got it. It can be obtained by multiplying the very first equality with r/2.
When alpha is really small, you have this really long radius*. As alpha tends to zero, r will tend to infinity. So the area might be pretty large.

light wagon
#

what's trigonometry?

light solar
#

suck a toe

#

i mean sah coh toa

#

my bad

#

no need to thank me @light wagon

light wagon
#

Thank you @light solar

#

Really useful info indeed

light solar
#

no worries buddy boo boo

#

my bad is soh cah toa not sah coh toa

upper karma
#

hello

#

is this correct

#

wait wrong channel

mystic karma
stray schooner
#

Help pls

winter pumice
stray schooner
#

cotangent 2a
2 cotangent a

winter pumice
stray schooner
#

Yes, we have these in all textbooks

winter pumice
#

are you sure

somber coyoteBOT
#

Disorganized

stray schooner
#

Yes

somber coyoteBOT
#

Disorganized

stray schooner
#

We have Russian textbooks, we write tangent and cotangent - tg, ctg

winter pumice
#

ok

#

Ok so you remember how there are laws of exponents and logarithms?

#

there's a really long version of that for trigonometric identities.

#

"trigonometric identities". Usually if you search that, you get a short list. But sometimes you get longer lists.

#

First one might require the product formulas for sine and cosine

#

let me look at it a min

#

*let me try it

winter pumice
# stray schooner

Solved part A by reorganizing top and bottom, using sum-to-product identities.

#

Cosine is an even function so it didnt matter how I ordered the first 2 terms in top and bottom when I used the identities.

silent plank
#

how much trig have you learned?

#

have you learned about sine,cosine,tan yet?

#

ok

#

which trig function do you think would be most useful here?

#

no

#

relative to the 67° angle,
can you identify the position of the side x

#

no

shut finch
#

Romanov can I also help please

silent plank
#

the side x isn't touching the 67° angle

shut finch
#

Yes sir

silent plank
#

yes x is opposite the 67° angle

#

can you identify the position of the 2m side relative to the 67° angle

#

yes

#

so you have the angle, the opp and the adj

#

yes

shut finch
#

Yeah you would do tan(67) /2 ?

#

Yh

#

Yeah I’m pretty sure you do tan(67)/2

#

Since toa

#

You put it in brackets on the calculator

lone copper
#

x=(2 tan 67deg)m

#

at least show that u know
tan 67deg=x/2

mystic karma
#

how do you calulate trignometric thetas for various angles

#

for now i just memorised trig ratios for 0, 30 , 60 and 90

#

for example how do i calculate the value of tan67 deg ?

signal swallow
#

put it in a calculator

mystic karma
#

i could but when i don't have calculator sitting around ?

signal swallow
#

you could do a taylor expansion if you really want

#

wouldn't be fun though

#

and it wouldn't be exact

mystic karma
#

ok thanks

#

in your country are calculators allowed in high schools ?

signal swallow
#

yes

mystic karma
#

oh i see

#

even in exams ?

signal swallow
#

depends

#

but normally if i'm not allowed a calculator on an exam, the exam doesn't need a calculator

mystic karma
#

i see

signal swallow
#

they use easy numbers that i can work by hand, the exam is more of a test of concept

mystic karma
#

understandable

#

so what i understand up until this point , there are like 5 strategies to prove trignometric identities -

#

1direct identity use

#

2 lcm

#

3 convert into sin and cos

#

4 rationalise ( only works for sin and cos)

#

5 using polynomial identities

#

can anything be added or corrected ?

signal swallow
#

haven't proved trig identities in a bit, but seems about right

#

factoring is also useful

mystic karma
#

whats factoring ?

signal swallow
#

$x^2-4=(x+2)(x-2)$

somber coyoteBOT
#

a disappointing son

mystic karma
#

oh yes

signal swallow
#

$x^3-3x^2+2x=x(x^2-3x+2)$

somber coyoteBOT
#

a disappointing son

mystic karma
#

i see this getting used a lot

#

thanks i will add it to the list

signal swallow
#

👍

silent plank
#

what's your issue with this?

split agate
#

hi can someone help me with my math hw

#

im in geometry

split agate
#

i have serveral questions i need help with tho

worn sigil
#

Can someone explain to me why that is the period

#

<@&286206848099549185>

#

Isn't finding the period 2pi/b

#

and not pi/b

#

why is that saying pi/(1/2)

#

pls ping me

neon grotto
#

Hey! Can someone help me with this: A square ABCD is given. Points P and Q are taken on the sides AB and BC such that the BP is equal to the BQ.BH is the height of the triangle BPC. Find the angle DHQ

neon grotto
#

h is on CP

winter pumice
#

Please screenshot the problem so we get the original statement and any figures it refers to

neon grotto
#

can i send you a photo of my figure@

#

@winter pumice

winter pumice
#

Put it up here so everyone can refer to it

#

...until it gets buried over the next few days

#

Since Discord 'forums' move quick

neon grotto
#

but the problem is not in english

winter pumice
#

Do you know how to attach images in Discord?

#

Oh

#

What language

neon grotto
#

Bulgarian

winter pumice
#

Can you copy-paste the text?

neon grotto
#

no

winter pumice
#

Like, is the original problem digital or on paper

#

Ok

#

Just screenshot it anyway

neon grotto
#

can you help me with the problem

winter pumice
#

I probably have to translate it first, but maybe I dont, depends

neon grotto
#

on paper is written even more unclear

#

thats why i wrote it down

winter pumice
#

You can translate it. Replace every instance of a string of letters with the Bulgarian word for something else. Pie, maybe (the pastry, not the number), run it through Google Translate, and then bacl-substitute the strings of letters

#

Please put the screenshit up though so we can compare it

#

Ok, how about this: is H an intersection point?

#

Can you just draw the figure

#

Because the description sounds good until H comes out of nowhere

#

@neon grotto

neon grotto
#

give me a second

#

i have written on the paper sorry

#

@winter pumice is it good now?

winter pumice
#

catshrug probably, it makes the last two triangles make sense

#

and the height

winter pumice
#

@neon grotto I suspect that tri HBC is similar to tri HCD

neon grotto
#

i dont think so

#

By the way dont continue torturing yourself i think i solved the problem!

winter pumice
#

Oh good

neon grotto
#

Thank you for your time and help

winter pumice
#

What did you get?

neon grotto
#

angle dhq is 90 degrees

winter pumice
#

Wow, really?

neon grotto
#

yeah

#

thank you again

#

good bye

winter pumice
#

Ok, bye

neon grotto
#

have a wonderful day

upper karma
#

fish

uncut summit
#

hello

#

can someone please help me with this question

upper karma
#

Maybe try draw it i cant help you now cuz im in a car

nocturne remnant
#

Oops I mixed up B and A

#

But notice that the 2 similar triangles must both contain theta and 180-theta

#

Which is not normally possible (as the remaining angle would be 0)

#

Unless…UNLESS!
theta = 180-theta

#

So that gives theta = 90

copper jackal
#

I dont know where to post this but can somoene please tell me how to get the bisector of a line pls ping if you want to send a solution cause i have a maths test tomorrow

uncut summit
#

Thanks elon

upper merlin
upper karma
#

imma have to review this

upper karma
#

-sin2x = ?

#

what cos

dusky surge
#

cos means cosine.

upper karma
#

help

winter pumice
# upper karma

The area of trapezium ACFD is the sum of the areas of tri ACD and tri CDF

#

We know that AC and DF are parallel because the planes they are in are parallel, and they are hypotenuses of similar triangles (tri ABC and tri DEF by SAS-similarity).

#

This means trapezium ACFD is a plane figure

#

This is why we know we can add the triangle areas we picked: it wont matter how we cut the trapezium up because all its points are coplanar

#

(Somebody pop in here and tell me every "trapezium" is a plane figure)

#

Anyway. Should be easy for you to take it from there, calculating the areas of the triangles in the trapezium, because they are right triangles as well (justify this!) and you can get their side lengths easily. Let me know if you get stuck.

upper karma
#

i tried for atleast but hour

#

idk

winter pumice
#

I have not written anything down to figure out this will work, try again following the steps I described

upper karma
#

I did

winter pumice
#

Ok, what are the side lengths of ABC and DEF

upper karma
#

I cant figure it out

winter pumice
#

^ you dont know how to solve a right triangle given 2 of the 3 sides?

upper karma
#

½bxh?

winter pumice
#

Thats an area formula

upper karma
#

oh

winter pumice
#

What formula gives you the sides of a right triangle

upper karma
#

no clue

winter pumice
#

Get a clue then: Google it

upper karma
#

pythagoureous ?

winter pumice
#

Yes

upper karma
#

a²+b²=c²

#

?

#

ye

winter pumice
#

Yes

#

You only need the 2 formulas you listed to solve the problem

#

Plus a little logic

upper karma
#

6²+6²=12²

#

?

winter pumice
#

No

#

c is unknown to you

upper karma
#

oh

#

so

#

6²+6²=c²

winter pumice
#

Use the labels

#

Yeah

#

But what sides are you talking about

upper karma
#

I'm confused a lot en

#

rn

#

top right

winter pumice
#

Ok

#

(DE)^2 + (EF)^2 = (DF)^2

#

So then
(6)^2 + (6)^2 = (DF)^2

#

36 + 36 = (DF)^2

#

72 = (DF)^2

#

what next?

upper karma
#

find out Df?

winter pumice
#

How

upper karma
#

idk

winter pumice
#

What is the inverse of squaring an unknown?

#

*what is the inverse of squaring something

upper karma
#

I not even onto pythagorous yet

storm portal
#

@winter pumice Taking the square root

#

$({\sqrt x})^2 = x$

somber coyoteBOT
storm portal
#

Just be careful with signs.

winter pumice
#

Thanks Shen, for confusing me with OP

#

But I guess its good the definition is here now

storm portal
#

Lmao XD

#

That's my bad

winter pumice
#

Nah, its good, it's pretty

storm portal
#

Thanks 😅

#

Wasn't sure if I should delete it because you're trying to get him to think about it

Respect 👊

winter pumice
upper karma
#

no

#

its for a volantery maths competition

winter pumice
#

Pythagorean Theorem comes up in Math I

#

Are you high school?

upper karma
#

irish education system is bad

#

yes high school

winter pumice
#

Did you cover the distance formula yet?

upper karma
#

yes

winter pumice
#

That's a form of Pythagorus. You guys have covered this

#

It would have come up by now

upper karma
#

I covered that in science

#

time speed distance?

winter pumice
#

Pythagoras is simpler case

#

No, not rates

upper karma
#

oh then no

winter pumice
#

You already listed the formula for Pythagoras, are you saying you don't know how and have never taken a square root?

upper karma
#

you phrased it wierd

#

inverse of squaring and unknown?

winter pumice
#

Taking a square root is an inverse operation to squaring

#

If you take the square root of x^2, you get x again

upper karma
#

yes ik

winter pumice
#

...because they are inverse-operations

upper karma
#

its like

#

xx/x x cancels out so it'd ×/×

winter pumice
#

This is the way I like to explain it:

#

x | x^2

1 | 1
2 | 4
3 | 9
4 | 16
5 | 25
6 | 36

#

When we square the input x, we are doing x*x

#

So we go from the left column entry to the right column entry

#

$\sqrt{x}$

somber coyoteBOT
#

Disorganized

winter pumice
#

is a function that can take us from an entry in the right column BACK to the entry in the left

#

It tells you what number got squared

#

So $\sqrt{36}=\sqrt{6^2}=6$

somber coyoteBOT
#

Disorganized

winter pumice
#

@upper karma understand?

upper karma
#

ye

#

so sqr of 81 = 9

storm portal
winter pumice
#

The list above is easy b.c. everything on the right is a PERFECT SQUARE: some number times itself.

#

But getting back to above...

winter pumice
#

But 72 = 36*2

#

and 36 IS a perfect square

#

So we do

#

$\sqrt{72}=\sqrt{36\cdot2}=\sqrt{36}\sqrt{2}=6\sqrt{2}$

somber coyoteBOT
#

Disorganized

winter pumice
#

and that's just fine for us.

#

BTW, we know we can do this from Laws of Roots (Exponents), which you might not have seen in detail yet

#

Don't worry about it

#

Splitting the root like this under multiplication is allowed.

#

You need to get the hypotenuse of the triangle on the front face now. Try it

#

AC

vital fractal
upper karma
rare sierra
#

just the last one I think

dense belfry
#

if i have the relation $4\sin\left(x\right)<3\cos\left(x\right)$ is there a way that i can rewrite this as a specific inequality for $x$?

somber coyoteBOT
#

aquaticape

dense belfry
#

for example, 2 radians works for tan but not for the original inequality

upper merlin
upper merlin
#

i ran a script which generated random points just to make sure there wasn't any printing mistake in the question

#

it seems to show that the ques is correct

mystic karma
upper merlin
mystic karma
mystic karma
upper merlin
mystic karma
#

oh ok

chrome laurel
#

hey

#

If x is an angle in the third quadrant and csc(x)= -13/5, find the value for 3sin^2(x)-2cos(x) as a fraction with no decimals.

#

can anyone help me?

dark sparrow
#

have you made any progress so far?

chrome laurel
#

well i know how to solve for x kind of, but how does it being in the third quadrant affect it

dark sparrow
#

you don't need the value of x itself here

chrome laurel
#

huh?

dark sparrow
#

the fact that x is in Q3 tells you what signs sin(x) and cos(x) are

#

hopefully you are able to calculate sin(x) directly from what's given to you, and then cos(x) from that and the Pythagorean identity?

chrome laurel
#

hm

#

okay i'll see

#

thanks very much

light arch
#

75

#

Bro you cheating in Kahoot or what

#

Xddddd

dark sparrow
#

@light arch don't give out answers

#

@rocky light don't ask for answers

lime crownBOT
#
Rule 7

When asking for help, do not insist on getting just the answer; we are here to help you learn, not cheat. Likewise, if you are providing help to others, try your best to explain and elaborate instead of simply giving away the answer.

dark sparrow
#

...

upper karma
#

Same angle, equal the terms and voila

dark sparrow
#

||sounds like someone is here in bad faith||

silk charm
#

is this a graded, timed evaluation?

#

oh, we do care

dark sparrow
#

"i don't care therefore the rules shouldn't apply to me"

#

rock solid logic

light arch
#

Bro this dude be cheating in his 3rd grade homework

silk charm
light arch
#

Who cares lol

silk charm
dark sparrow
#

is "rock solid logic (sarcastic)" actually an expression in english thonkstein

silk charm
#

i've heard solid and air tight

#

not rock solid, but seems like a variant

dark sparrow
#

in russian we say железная логика which means "iron logic"

upper karma
#

Rock solid is a thing I think

light arch
#

@upper karma not in a sarcastic way

upper karma
#

Wdym? Just say it sarcastically duh

light arch
dark sparrow
light arch
#

@dark sparrow what's your major if I may ask, i see you a lot here, you know your stuff

dark sparrow
#

some flavor of applied math

#

i'm doing masters rn

#

i guess less applied than what i did in bachelors

#

...hello

#

do i know you?

#

<@&268886789983436800>

silk charm
#

ah someone beat me to it

dark sparrow
#

what even was this

viral jolt
#

b&

#

just link spam

dark sparrow
#

"fuck ass furry"

silk charm
#

it might be an alt of the person i just banned for cheating

#

given what they said

#

these people

dark sparrow
#

im not even like. a Furry furry

worthy igloo
#

it's the internet ma its not that deep

upper karma
#

how do I solve this

#

by using cosine law

silent plank
#

cosine law is complete overkill for this

#

instead consider similar triangles

nocturne remnant
#

They are required to use cosine lawcatThin4K
And the similarity is probably a side effect of trying to make everything whole numbers

silent plank
#

are they actually required?

sonic nova
#

you would use it to find an angle C

silent plank
#

or did they assume that law would be most useful here

sonic nova
#

then sub it into cosine rule again to figure out the side

upper karma
weary drift
#

assuming so is pedagogically beneficial

upper karma
#

Can someone explain to me what i did wrong? Im confused

winter pumice
#

The ray from O to M is stretched out by 3. Where is this new point?

#

Draw it

stuck iris
#

Is it possible to express $\cos(a - b) = f(a) \times g(b)$ ?

somber coyoteBOT
stuck iris
#

I've tried factorising it in numerous ways but i feel like its not possible? is this a provable thing?

dark sparrow
#

it most definitely isn't possible.

#

if it were, then the solution set of cos(a-b)=0 would consist purely of horizontal and vertical straight lines on the coordinate plane

#

which it does not

#

@stuck iris

upper karma
#

also keeping a=b implies f(a)g(a)=1 or g(a)=1/f(a) which is identically true

#

which means we could write cos(a-b)=f(a)/f(b) and since cosine can be zero it implies either f can be zero or infinite

#

both of which implies cosine should not be bounded but we know cosine is very well bounded so hence this assumption is false

#

though yea this is a pretty weak argument but pretty good insight regarding the problem

stuck iris
upper karma
#

welp

#

geometry gods wya?

nocturne remnant
#

Try to find the exact positions of the vertices of the triangle by using the info already given

echo solstice
upper merlin
#

I solved for the 1st part, how do I go about doing the 2nd part?

dusky surge
#

Does it help if you prove that triangle ABC is similar to triangle A'B'C'?

#

Since you will find some angles in same segment if the circumcircle of A'B'C' is constructed

kindred coral
#

How would I be able to determine what single shape corresponds to the requirement if several shapes fit the description?

loud shard
#

can someone please help me with this?

bleak fox
stray pollen
#

help

cursive vapor
#

hi
i have an exercise
given the are of circular sector= 16pi find the perimeter of this sector

#

just tag me please

hollow plume
# stray pollen
  1. Since angles 4 and 7 make a straight line (180 degrees), the angles are supplementary.
  2. Angle 12 is 90 degrees, you can assume that the 2 other supplements are equal to 90 degrees. Hence they’re complementary. (Angles 10, 12, and 3) make a 180 degree straight line.
  3. Angles 4 and 5 are not adjacent to each other to make a straight line. They’re not a linear pair.
  4. Angles 2 and 10 are not directly opposite from each other. Also, angle 10 is less than 90 degrees and angle 2 is greater than 90 degrees.
  5. Angles 1 and 2 are adjacent to each other and make a straight line. They are a linear pair.
  6. Angles 7 and 9 are directly opposite from each other. Since angles 4 and 7 make 180 degrees and angles 9 and 8 also make 180 degrees, all 4 angles make 360 degrees. Again, angles 7 and 9 are directly opposite. Hence, they’re vertical angles
hollow plume
#

@stray pollen ^^

stray pollen
#

Thank you so much

pastel pewter
#

hi , can somebody help me please, how to get sine and cosine value of an angle with unit circle? for example sine 1 degrees, sine 27,7 degrees, or sine 89 degrees

lapis pine
#

Middle angle will be

quiet blade
#

Not enough information to determine

raw tiger
pastel pewter
upper karma
#

Hi how can I solve this

#

I know the answer by the way... just want to know why

#

Ignore what is there

winged falcon
#

i don't even know how to being with this one tbh

upper karma
quiet blade
upper karma
#

10 cm

quiet blade
#

Great, and the hypotenuse

upper karma
quiet blade
#

What is the area of the triangle?

#

Actually don't calculate it

#

just tell me with words, what times what

upper karma
#

Half base multiply with height

#

Like half square

quiet blade
#

Aha, so you have PQ*QR/2 = PR*(height you are looking for)/2

#

and you have all other values except the height

upper karma
quiet blade
#

H right, so the area of the triangle is also base = PR times height H, divided by 2

upper karma
#

Yes

quiet blade
#

Then use this PQ*QR/2 = PR*(height you are looking for)/2

upper karma
#

Wait u can look at it from diffrence angles and get it ?

quiet blade
#

Yes, the formula is the base of a triangle, multiplied with the altitude that falls on that base, divided by 2

#

There are three bases, therefore 3 instances of the same formula

upper karma
#

I think the question is more directed toward the altitude of hypotenuse theorm that I know nothing about

#

But... u like hacked the question

#

That's so cool

quiet blade
#

I don't exactly know what that theorem is, but most people would solve it as I did

#

And that theorem is most likely a consequence of that we went over

#

It probably is PQ*QR / PR is the altitude

quiet blade
upper karma
#

Yeah... that's correct

#

Thanks so much

delicate rampart
#

cos(a-b) = cos(b-a) for all a, b?

#

cos(a-b) = cos(-(b-a)) = cos(b-a)

livid moss
#

Are you asking if that's true? Then yes

clear sun
#

Can I have sum help on this

#

<@&286206848099549185>

nocturne remnant
#

ABCD is parallelogram

#

cuz you have two parallel and equal-length sides

urban bolt
#

How to solve that 2 problems

quiet marlin
#

Unit circle

urban bolt
#

But then, I dont know what todo

quiet marlin
#

Wot does it equal

#

Or not equal

#

But you get what I mean

urban bolt
#

@quiet marlin

urban bolt
#

Ohh, I get how to solve that, I was just need to take arccosine of both sides, and there is ultraeasy inequality $$sin(x-\pi/6) < 5\pi/18$$

somber coyoteBOT
#

qcanser

thorny forge
#

what does it mean by (b)

silent plank
#

start by drawing two tangent lines from the person to the tank

thorny forge
#

yes oki i just dont get how ur meant to find the cicumference visible to person

silent plank
#

the part that's visible is the arc between the two points of tangency

thorny forge
#

hmm

silent plank
#

consider properties of radii, tangents and right triangle trig

thorny forge
#

i get it abit but how do i find the angle

silent plank
#

right triangle trig

thorny forge
#

i dont get that

molten rivet
thorny forge
#

to the edge of the red portion

narrow sleet
#

If you draw a line from the centre to the edge, you form a right angled triangle

#

Ur hypothenuse is 80

#

One of your side is 20

#

so....

thorny forge
#

mm im having trouble visualising it do u mind drawing it its okai if not T-T

#

ohhh wait

#

im supposed to find this angle using that and use that angle to find the length seen

narrow sleet
#

@thorny forge

#

You can use trig to find the angle

thorny forge
upper karma
#

please help in this ques..

mossy pike
#

Try to think about angles which are 60 degrees. Perhaps their sine or cosine will come useful.

#

Also you can use the intersection of AC and BD, call it O, and find AB = AC = AO + OC.

#

It seems like the answer is 6/cos(80)

#

approx 35

upper karma
#

Question:
If three angles of a quadrilateral are equal then it is a parallelogram. (true/false)

silent plank
#

wdym by 3 angles of a parallel

placid topaz
#

Please help in this problems

upper karma
winter pumice
mossy pike
upper karma
#

please help

#

ive got this so far, cant get 4

delicate lintel
#

any tips for proofs?

muted sparrow
upper karma
#

Just started studying this, the first method I learned, wondering if I did I correctly because I’m trying to understand it.

weary scaffold
#

can someone help me with a few trigonometry questions?

upper karma
thorny forge
#

i understand i have to do 6400 x sin(15) but what do i do after that

dark sparrow
#

@thorny forge it's 6400 cos(15°), not 6400 sin(15°). also you don't "have to" do anything. there's no such thing as "having to" do something in math.

#

once you have written that down, it's time to put 6400 * cos(15) into a calculator, then round to the nearest kilometer

#

also don't use the letter x to denote multiplication.

thorny forge
#

ohhhh sorry i meant cos aaa but the answer is less than what the calculator gives me, am i meant to take away something after it

dark sparrow
#

what does the calculator give you?

thorny forge
#

calculator gives me 6223 but answer is 6182, its same with the rest of the questions asking for radius,, i dont know what i take away after

dark sparrow
#

6223...?

#

can you please show me what you are entering into the calculator?

thorny forge
#

ohh noo is that wrong

#

i entered 6400 times cos(15)

dark sparrow
#

it appears to be wrong, and i want to know exactly where it went wrong.

#

i want you to take a picture or screenshot of exactly what you're entering in there

thorny forge
#

oh okay

#

when you enter it in yours what does it say

dark sparrow
#

it says this, which matches up with what you said was the book's answer.

#

but that's not what matters right now.