#geometry-and-trigonometry

1 messages · Page 357 of 1

upper karma
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i think the second equation has no use

cloud stump
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how come the sum of the angles of a triangle is an axiom

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wut

dark sparrow
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it is not

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it's not an axiom

cloud stump
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this guy put it as an axiom that's why i say it

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@grim rampart does "a" stand for axiom? it's a theorem

grim rampart
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not sure but hes confusing me

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he said its an assumption

dark sparrow
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'assumption' as in 'we will take this for granted for the time being'?

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or what

cloud stump
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your A2 is an axiom, it's one of euclid postulates

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but a5 is not an axiom

dark sparrow
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is A2 an axiom? hold on

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i could have sworn it was derived from something else

grim rampart
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ah yeah

dark sparrow
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though of course different axiomatizations of geometry exist

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so maybe all this is pointless

cloud stump
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Yeah true

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@grim rampart just make sure to not mix up axioms with theorems like in the specific axiom system you're using

grim rampart
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oh okay

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how can i solve certain geometry problems

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i get stuck on how to start the proofs

dark sparrow
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make a diagram depicting all the info you're given

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attempt to recognize familiar objects such as triangles or arrangements of straight lines

lost jetty
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how can i find A?

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Angle A

dark sparrow
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just to copy your diagram and make it slightly more readable

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i have a stinking feeling like itll involve a lot of fuckery with the laws of sines and cosines

silk patio
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AD is parallel to BC?

upper karma
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if you make a copy of ABD and paste AB along CD (calling the new point E), ECBD will be a trapezium and point A will coincide C, so angle A will be equal to D = 50

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the fact that its a trapezium can be proven by similar triangles ig

silk patio
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The trapezium trick is pretty

upper karma
lofty oxide
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does anyone know why inverse functions are reflected in the line y=x? if we have a point (x,y) and we flip the order, how do we know those two points are reflected in the line y=x?

balmy stream
lofty oxide
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is there like a geometric proof of this?

dreamy ridge
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Not sure of a geometric proof but think about what an inverse function does intuitively, for the original function it takes an input and maps that to an output. The inverse will reverse that process and revert The new input (which is actually the output of the original), into the output of the new function ( which is the input of the original)

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When we find an inverse function algebraically, we swap the x and y’s in order for this to occur

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Hence the functions are reflections of each other in the line y=x

heady bronze
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Hi! So I tried this problem but I keep getting 32 but my teacher says it's wrong and I'm not sure what to do-

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I believe this is coordinate geometry

dreamy ridge
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How are you working out 32 btw?

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So first find the vector PQ and the vector QR, these are perpendicular to each other. Find the magnitudes of these vectors (the lengths) and multiply them together for the area of the rectangle

smoky rover
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cansomeone tell me the answer

heady bronze
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I did two things, I tried this square method which led me to 32 and also the distance formula which got me to 25

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Wait

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6 square is not 12 hold on

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Hmm she says the answer is 30

dreamy ridge
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6^2 +3^2

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Is 36+ 9

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45*

heady bronze
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Oh my I wrote 48 that's why-

dreamy ridge
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So the other length is root 45, so area = root 45 x root 20
Which is root 900
Which is 30 units^2

heady bronze
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OHHH

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THANK YOU SO MUCHH!!!

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There's actually another problem as well-

dreamy ridge
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Go ahead

heady bronze
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I think the formula was
1/2 d1 * d2

dreamy ridge
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See the triangle WXY? All you need to use is the fact that angles in a triangle sum to 180, so that 8x-3+3x+12 + <WXY =180

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Then solve for the angle

heady bronze
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Ohhhh

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IMMA TRY IT!!

dreamy ridge
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Unless I’m under simplifying it lol

heady bronze
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Oop- Honestly Imma take your word for it!! THANK YOU!!

dreamy ridge
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But you need to find x first

heady bronze
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Oh so would we just do 8x-3+3x+12 =180?

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find x and then solve for wxy?

dreamy ridge
heady bronze
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Oh I just took the equation that you gave but took the wxy out-

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I'm guessing thats not correct-

dreamy ridge
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Bc it’s a rhombus the supplementary angles sum to 180, so that 8x-3+5x+6 + wxy also= 180

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So now we have simultaneous equations

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Am I overcomplicating this horrifically? Probably

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XD

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But yeah if we can solve the simultaneous equations we can work out wxy

heady bronze
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O h u h-

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I'm so sorry I'm stuckk

dreamy ridge
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Basically

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These angles sum to 180:

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And so do these angles

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So we can form 2 equations in terms of x and WXY

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And I’m assuming you know how to solve simultaneous equations I’m sure you can get x and the angle that way

heady bronze
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Ohhhh so we would first solve for x

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by putting two equations together?

dreamy ridge
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Yep

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Bc that’d eliminate the WXY

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And then you can sub the value of x in

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To find the angle

heady bronze
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Ohhh

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So we could do

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8x-3 + 5x + 6

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and then Find x that way-

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or wait

dreamy ridge
heady bronze
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Ohh

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OH

dreamy ridge
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Solve that to find x

heady bronze
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SO WE PUT THEM EQUAL TO EACH OTHER-

dreamy ridge
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Yes

heady bronze
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OHHH

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TYTYTY

dreamy ridge
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Bc they’re both 180

heady bronze
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Ahh I see

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So ultimately it would be
8x - 3 + 3x + 12 = 8x - 3 + 5x + 6

dreamy ridge
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Yep

heady bronze
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Ah alrightyyy!! Lmayoo

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I got x equals 3-

dreamy ridge
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Yep

heady bronze
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Yaya!

dreamy ridge
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Then just 180 - (8x-3)-(3x+12) for the angle

heady bronze
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Would I substitute x in?

dreamy ridge
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Yes sorry that’s what I meant

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Using x= 3

heady bronze
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Ah alrighty!!

dreamy ridge
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Does it give you the right answer?

heady bronze
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Ah it's taking a bit sorry!! I was moving rooms

dreamy ridge
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No worries lol I was just eager to know if all that was for nothing haha, haven’t done angles in years

heady bronze
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Oooh alrighty!!

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It's weird

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I got 180-

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wait

dreamy ridge
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Hmm I didn’t get that

heady bronze
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138?

dreamy ridge
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I got 180-21-21

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Yeah

heady bronze
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Oh wait

dreamy ridge
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I got 138

heady bronze
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Yay!

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I think I forgot that 21 was also negative

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So 138 is the final answer-

dreamy ridge
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I should hope so lol

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Hopefully it’s right

heady bronze
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Hopefullyyyy!!! THANK YOU SO MUCCHHH

dreamy ridge
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No problem haha

heady bronze
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: DDDD

balmy stream
livid glen
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Hi, I would like to know how to solve the question 3. It says: "Find the equations of the tangent lines to the elipse (first equation describes the elipse) that are parallel to the line (equation of the line)

wise pawn
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are you allowed to use calculus?

livid glen
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no unu

wise pawn
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good luck 👍

livid glen
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xD

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I´ve been trying to solve it with a friend for about 3 hours

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time to mail my teacher, i guess

wise pawn
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it's probably not that bad to solve tbh, make a line with the same slope with an undetermined y-intercept and make it intersect at one point, so that probably will end up amounting to setting a discriminant=0

cloud stump
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Creo que había un método fácil para determinar tangentes a cónicas

willow kiln
tepid path
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I feel like if we scale the x and y axis properly and shift the origin, this will just be the same as finding a tangent to a circle with origin as centre of a given slope, and because of the perpendicularity of tangents to the line joining the radius i think this shouldn’t be so bad

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Oh i just saw merosity’s answer, i think even in my way you would need to solve a quadratic so it isn’t really any better

fickle trout
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Hey guys, I tried in the questions channels, without any luck. Since it's geometry, I thought I might try here:

I have two 2d coordinate systems, and I need a formula to transform a point from system 1 to system two. All I have is the information that 3051/7966 is -127.94/49.1 and that 9664.96/8836.96 is -114.4/155.55

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Someone told me to normalize, and then compare angles and whatnot, but I'm unable to pick up from there.

umbral snow
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Yike that's jibberish.
What is 3051/7966?
What does it mean for something to be "is"?

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Maybe your point is (3051, 7966) and after the transformation you expect it to go to (-127.94, 49.1)?

fickle trout
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yes 😉

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and the other point too

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my gut feeling tells me with those two "point pairs" it should be possible to come up with a transformation "formula", but I have no idea how

umbral snow
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,w solve system -127.94 = 3051a + 7966b, 49.1 = 3051c + 7966d, -144.4 = 9664.96a + 8836.96b, 155.55 = 9664.96c + 8836.96d

fickle trout
umbral snow
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Okay so there's exactly one linear system that can be used as a mapping for your points

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If you keep (0,0) to (0,0) and stretch/rotate everything else, it can be done

fickle trout
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Well, I can't do it 🤣

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If it's not hard to do for you, could you do it for me? 😊

umbral snow
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I don't know what "do" means here

fickle trout
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Well, come up with a "formula" to transform arbitrary points from the first coordinate system to the second. Sorry if I don't know the right words to ask the question, bear with me, I'm an old man.

umbral snow
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Right. So if your point is (x,y) and you want to transform to (u,v) then:
u = ax + by
v = cx + dy

Where a,b,c,d are those numbers in the picture

fickle trout
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oh! I'll try that, thanks!

umbral snow
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They should probably be written as decimals oop Wolfram just didn't feel like doing that

fickle trout
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sure, I can do that 😉

umbral snow
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Good luck with it! Feel free to ask if you need anything else with it

fickle trout
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thank you very much

fickle trout
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there was a typo I think

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-114.4 became -144.4 😉

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it works though! thanks!

dapper bronze
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Can someone help me with my practice math test

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I will pay

dense trellis
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@dapper bronze i can help.

cloud stump
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Have you guys read the rules?

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You both gonna get banned

silk patio
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It’s a practice test, what’s the rule against that

humble pulsar
narrow plinth
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The distance between A and D is 1
It's a equal sided triangle in a circle
Find a,CD and the radius

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I've tried to use the cosine theorem after i got that 1+BD=CD but idk hot to continue

cloud stump
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You have to calculate DCA

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The angle DCA

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Use the fact it is a cyclic quadrilateral

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@narrow plinth

narrow plinth
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Aha

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Dca is the one near the C point?

cloud stump
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It's the angle formed by DC and CA

narrow plinth
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Okay thx

cloud stump
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It's an inscribed angle

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After that you'll notice AD is the side of a regular polygon inscribed in the circumference

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And then u get the radius from that

narrow plinth
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One more question

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I tried to do this

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Is the sin of the angle CAD times CD equal to the gray line

cloud stump
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Are you required to use trigonometry?

narrow plinth
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No

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But i don't understand the priperties of a cyclic quadrilateral

cloud stump
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Okay do you know inscribed angles?

narrow plinth
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Yes

cloud stump
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Okay, since the angles DAB and BCD are both subtended by the same arch, they are equal

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And you know BCA because that's an equilateral triangle, so you can take the difference to get DCA

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Btw all the answers are nested radicals

narrow plinth
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Aka they'll be some ugly answers

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Ok i'll try to redo the thing after dinner

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Thx

cloud stump
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Okay

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Np

empty slate
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Is it possible to divide a circle's circumference by the distance a point has traveled along said circle to get the arc's degree of measure?

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Or am I wildly drawing false thoughts

wise pawn
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nearly

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it might be good to set up a ratio

frigid tundra
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hello

wise pawn
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the path travelled / circumference = angle degree travelled / 360 degrees

frigid tundra
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a basic EFG prism such as EF = 3cm, EG = 4cm and FG = 5cm and the height of 10cm
a) calculate the volume of the prism
b) calculate the lateral surface of the prism
c) calculate the total area of ​​the prism

stuck edge
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how do I find b (the period) of the trig equation y = 2sin(x)+1?

frigid tundra
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someone help me w this geometry hw 💔

median needle
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can someone help me with this

static python
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the amplitude would be 3

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period is 2pi/2, which is pi

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phase shift is none

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cause there's nothing being subtracted or added to x (in paranthesis)

quick crag
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can somebody help plz

upper karma
rapid tartan
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anyone have a idea?

nova rose
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yo just wanna share this awesome video i just found

uncut path
rapid tartan
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which is? @uncut path

uncut path
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Pi r^2 * theta/360

rapid tartan
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what’s the theta? @uncut path

uncut path
zenith garnet
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How can I find tan(275), given sin(85) = 0.996? Without using any calculators to directly calculate the value.

finite edge
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tan(275) = tan(275-360) = -tan(85) = -sin(85)/cos(85)

rapid tartan
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would it be 98? @uncut path

inland mountain
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Triangle xyz will undergo a transformation to create triangle x'y'z' which of the following rules will result im triangles that are the same size?

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Would it be the first and the 4th ones?

half patio
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A triangle has angles that measure 35°, 65°, and 80°. If the shortest side of the triangle is
18 inches, find the length of its longest side to the nearest inch.

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how would i solve something like this

manic plank
half patio
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cause of covid we aint rlly learn anything

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the course was all over

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and idk how to do it

manic plank
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Well there is more then one way to solve this, but I'm not sure what tools you can use. I assume you can use the trig functions and Pythagorean theorem at least?

dark sparrow
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law of sines would be key here

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it's absolutely necessary to solve the problem

manic plank
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Eh, you could use the same method to derive the law of sines to solve it without the law of sines too

dark sparrow
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it'd be exceedingly cumbersome

manic plank
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A little, yep. But some parts of the world still teach it by asking them to solve it without law of sines first.

dark sparrow
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@half patio do you have access to the law of sines?

half patio
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like cos sin?

dark sparrow
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$\frac{a}{\sin(A)} = \frac{b}{\sin(B)} = \frac{c}{\sin(C)}$

somber coyoteBOT
dark sparrow
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does this sound familiar to you?

half patio
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yeah i seen it before

dark sparrow
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this is the law of sines

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does your class/teacher/whatever allow you to use it?

half patio
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yes but we never learned ho

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w

dark sparrow
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make a diagram of your triangle

half patio
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and put all 3 angles in?

dark sparrow
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make a diagram of your triangle, label it ABC (for convenience), and label all angles with their values

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just the angles for now.

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then show me what you got.

half patio
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done

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oh

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take a pic igh brb

dark sparrow
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ping me once you upload the pic here.

half patio
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@dark sparrow

dark sparrow
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could've made the triangle not seem isosceles... but okay, whatever, we're not drawing it to scale anyway.

half patio
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ohh

dark sparrow
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this diagram is fine.

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it's not to scale, but it's fine.

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now, the shortest side of the triangle is 18 inches.

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are you able to identify, based on the angles, which side of ABC is the shortest?

half patio
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uhh they are all equal but

dark sparrow
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no.

half patio
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yeah i can pick one sure

dark sparrow
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no, they are not all equal.

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no, they are not all equal. this is not an equilateral triangle.

half patio
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the triangle i drew is equal diagram wise

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but i get what youre saying

dark sparrow
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and i said

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twice

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that this diagram is not to scale

half patio
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yeah i know

dark sparrow
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therefore the way sides appear cannot be relied upon.

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and yet you did just that.

half patio
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id say the side of b is shortest

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which would be 18 inches

dark sparrow
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"the side of b"?

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are you talking about the side opposite to angle B?

half patio
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yeah

dark sparrow
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okay, yes, you are correct. side AC is the shortest.

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now, the problem asks for the longest side.

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which side is the longest?

half patio
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it would be

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AB

dark sparrow
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uppercase.

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AB, yes.

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AB is the longest side.

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now, back to your diagram, label the side AC with its length 18 in, and label AB with the letter x

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and show me the diagram once you made these labels

half patio
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@dark sparrow

dark sparrow
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alright, this will do.

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now remember the law of sines.

half patio
dark sparrow
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yes.

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do you see how each fraction involves one of the sides and the angle opposite to it?

half patio
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18/sin(35) = x/sin(80)

dark sparrow
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no, this is not correct.

half patio
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oh no

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the 18 goes on b

dark sparrow
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and cut out the side we don't care about.

half patio
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like that?

dark sparrow
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yes, now this is correct.

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18/sin(35) = x/sin(80)

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are you able to solve for x?

half patio
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uhh not sure how to get rid of sin

dark sparrow
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sin(35) and sin(80) are just numbers.

half patio
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oh so

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18/35 = x/80

dark sparrow
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no.

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you cannot just erase the word "sin" from both sides of an equation just because you don't like trig.

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that'd be like erasing the digit 7 from everywhere in an equation.

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it's nonsense.

half patio
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understood

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so do we find sin before?

dark sparrow
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if you really insist on pulling out the calculator at this stage...

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i wouldn't do that.

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you're overthinking things.

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all it takes to solve for x is multiply both sides by sin(80)

half patio
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then the other sin would cancel out, but wouldnt it create another?

dark sparrow
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no! the sines would not cancel out!

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what is it with you and your urge to cancel things out in nonsensical ways!

half patio
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LOL i got no clue

dark sparrow
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sin(80) does not mean the product of 80 with a number called sin !!!

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the answer is x = 18 sin(80)/sin(35) !!!

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and NOW you can get your beloved calculator out and have it find the value of that.

half patio
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got you

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x=30.90527858

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i got that

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is it right?

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@dark sparrow

dark sparrow
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jeez, hell if i know

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but you need to round it to the nearest inch, which you definitely haven't done.

half patio
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that would be 31

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yeah

dark sparrow
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,w 18 * sin(80°)/sin(35°)

half patio
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tyy

vernal nacelle
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i need HELP with some ORTHONORMAL SYSTEM / TRIGONOMTERY

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show that OH x 4√5 = 4 x 8

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OH x EF = OE x OF

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how do i do

dark sparrow
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uh

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is there a diagram you didnt show us?

vernal nacelle
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yes im sending it sorry my internet is bad

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there

silent plank
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consider area of a triangle

vernal nacelle
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yes we got that

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its 16 cm squared

silent plank
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apply the formula for the area of triangle FOE in two different ways

vernal nacelle
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i

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think my calculations are wrong

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i did (FO x EO) / 2 for the area

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is that right

silent plank
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yes, that's one way to get the area

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what's another?

vernal nacelle
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sorry but whats considered the base here?

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which segment

silent plank
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Area = 1/2 bh where
h is the altitude relative to the respective base b

vernal nacelle
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ohhh

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(FE x OH) / 2 ?

silent plank
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yes

vernal nacelle
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but in the end i use (FE x OH) / 2 = 16 ?

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and replace numbers

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but what about the equation they gave us

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this is the question

silent plank
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(FO x EO) / 2
(FE x OH) / 2
can both be used to get the area of the triangle

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and would give you the same value. note that I at no point actually asked you to calculate the area of the triangle

vernal nacelle
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i see

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thanks

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we calculated the area in the question before

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so ill use that and write them both will equsl to 16

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thank you

empty slate
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I'm pretty sure a graph is needed, but wouldn't you be able to plug in A and t into the original equation?

lethal crow
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pls help

empty slate
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are you familiar with Pythagorean theorem? a^2+b^2=c^2?

lethal crow
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yea somewhat

empty slate
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let a=5 and 12=b, calculating those should allow you to find c

lethal crow
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then do i find the square root of c

empty slate
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yes, since you squared both 5 and 12, you would reverse the process and square root the result to find c

lethal crow
empty slate
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All angles in a triangle add up to 180 degrees; since you know two angles, can you figure out the 3rd using algebra?

lethal crow
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maybe

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idrk tho

empty slate
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If you want, explain to me the process you think is correct and I'll add on if needed?

lethal crow
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divide 36 and 3x by 3 to cancel out the 3 in 3x

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thats abt it

empty slate
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right idea, wrong application; add the two known angles together, 90 and 36, and subtract that from 180.

lethal crow
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then that will give me x?

empty slate
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That will give you what 3 * x equals

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divide the answer you got by 3, and that will leave you with x

lethal crow
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ok

empty slate
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What was your final answer for x?

lethal crow
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18

empty slate
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Nice

lethal crow
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how would i find x if theres no number with x

empty slate
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Using your last triangle, you would add 90 and 36, 126, and subtract 126 from 180

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180-126=54, or x

lethal crow
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oh so the number i get out of subtracting is x

empty slate
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yes

lethal crow
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ohh ok

empty slate
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oh, hold on

lethal crow
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i think i got it but idk how to do the other one

empty slate
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@lethal crow you could use the reciprocal of tangent to find x, since you have the opposite side with angle 25

lethal crow
empty slate
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Using the reciprocal of tangent, (cot), you would do cot25(x/8)

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@lethal crow or so I believe, I can't figure out my own question so I'm frying my brain over it

lethal crow
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so 25x/200?

empty slate
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it's been awhile since I've done that, but I don't think that's it. There's a lot of external equations that go into that one

lethal crow
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ok

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idk how to do SOHCAHTOA

empty slate
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Sin=o/h Cos=a/h Tan=o/a

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The thing to remember is these inputs will vary on what angle you choose, with the exception of the hypotenuse.

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You also need to use an angle other than the 90 that's provided

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@lethal crow

lethal crow
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ok

lethal crow
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@here ?

silent plank
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what's that number supposed to be for?

heady lagoon
#

Would anyone be able to help me personally with a couple find domain,range,period questions?

fervent valley
#

Does anyone understand quadratic graphs?

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Like finding vertx and how iys graphed?

humble pulsar
fervent valley
#

yes thank you

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could u help me pls?

umbral snow
#

Mosh is capable of helping you. I'm glad I could be of service.

fervent valley
#

Yes Mosh please assist me

umbral snow
#

Lol in the future just start with the question right away. What's up?

fervent valley
#

nono im stuck with the q so i cant proceed

umbral snow
#

Yeah what's the q?

fervent valley
#

so if u like look at A
The vertex would be ( -2, -3) right?
But there are 2 graphs that interesect at the same vertx
graph e and f
how am I supposed to know which one is the correct one?

umbral snow
#

One of those two graphs has more vertical stretch than the other

#

a and e have the same vertex, which has more vertical stretch?

upper karma
#

Anyone need math help?

rough brook
#

I’m stuck in a problem could someone help? I’m supposed to find the exact cube roots of the complex number, no decimals, and I’m supposed to use radians and leave my answer in polar form -4sqrr(2)(1-i)

#

@upper karma could you help me??

upper karma
rough brook
#

I don’t think I’m trying to find angles

#

I’m supposed to get the cube roots of the complex number

#

In polar form

upper karma
#

they gave you -4srt4 (times) 1-i

#

?

rough brook
#

I’ll send a pic

upper karma
#

aight

rough brook
#

You gonna be able to help??

umbral snow
#

Can you write it in polar form?

#

That is, r(cos(t) + isin(t)) for some r and t?

rough brook
#

The instructions say to find the exact cube root for that complex number

#

Then to leave the answer in polar form

umbral snow
#

Okay so putting it into polar form is the first step

rough brook
#

Ohh ok

umbral snow
#

If you can identify the magnitude and angle of the number, that's enough to put it into polar

rough brook
#

Would it be like 8(cos(3pi/4))…

#

+isin(3pi/4)

umbral snow
#

Sorry missed the negative haha. Yeah! That's perfect

#

Now Demoivre's theorem, says that when we take the cube root, we can put it into the sin and cos instead

#

A cube root of this number is
2(cos(π/4) + isin(π/4))

#

We can get another cube root by first changing the angle by 2π, then doing this

#

There's three cube roots to get

rough brook
#

I’m getting a little confused so I’m gonna plug in the cube root for sin and cos??

umbral snow
#

Instead of doing
[cos(t) + isin(t)]ⁿ

You can do
cos(nt) + isin(nt)

#

That's DeMoivre's theorem

#

n is 1/3 here

earnest basin
#

Hellooooo

#

Can someone help meeeee

#

@knotty merlin

#

<@&286206848099549185>

#

-_-

dark sparrow
#

[walks into a restaurant] "Hellooooo!!! Can someone serve me some food!!!!!!!!!"

#

@earnest basin this is what you sound like rn

livid moss
#

I would give Ann food before I helped Shoer with their unknown math problem.

earnest basin
#

Oh sorry i'm newbie

dark sparrow
#

you should, first and foremost, tell us what you need help with.

earnest basin
#

This is trigo, btw i think angle of depression

#

The what i can do part

livid moss
#

Can you draw a picture?

dark sparrow
#

this problem reads very weird to me

earnest basin
dark sparrow
#

it sounds like there's a lot of data missing

#

like... we are not told when or where the airplane lands. does it land at the airport? if it does, then how are we supposed to find how far it travels after landing?

#

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

#

what is this smiley react supposed to mean?

earnest basin
#

Idk i just did it lol

earnest basin
#

K

cloud stump
#

What the actual...

rapid tartan
#

i did one just like this with the correct equation and i got it wrong so i don’t rlly know what i was doing wrong it’s kinda confusing to me also

silent plank
#

what did you try?

#

show work

rapid tartan
#

i tried a similar question with this equation

#

@silent plank

silent plank
#

that's for the equation for radius,
you'd still need to go through a bit of work before applying that.

rapid tartan
#

yea ik i do and then later on i made the a and b the centers

silent plank
#

consider completing the square
and expressing the equation of the circle in centre form

rapid tartan
#

wdym(

#

?

silent plank
#

completing the square is the most common method for
converting the equation of a circle in general form to center/standard form
which will let you easily identify the centre and radius of the circle

ember loom
#

Can anyone help me with this question?

storm portal
#

@ember loom Corresponding Parts of congruent triangles are congruent

#

So given the congruence statement of ABCD = EFGH,

A corresponds to E
B corresponds to F
C corresponds to G
D corresponds to H

#

the same applies with angles and sides

ember loom
storm portal
#

you need a numerical value

ember loom
#

Ohhh

#

wait

#

what would the numerical value be? Do I add EFG togerthyer?

#

Oh nvm\

ember loom
storm portal
#

EFG = ABC, right?

#

If you can find the measure of angle ABC, then that's it

ember loom
storm portal
#

angle ABC ≠ angle A + angle B + angle C

ember loom
storm portal
ember loom
#

But this isnt numerical

storm portal
#

the measure of angle ABC is the measure of angle B

#

that's pretty much it

#

A and C specify the rays that make up the angle

ember loom
#

Hmm alright I think I understand

ember loom
#

Any help?

cursive python
#

hm

#

They are alternate interior angles

#

Because SJ || KW

ember loom
hoary moat
#

Hi. The exponential has sinh and cosh as its odd/even components. It turns out to be an important function. What about some function that has sin and cos as its odd/even components. It'd be f(x) = cos(x) + sin(x). Is that special or interesting somehow?

dark sparrow
#

not very - though it does happen to be a sinusoid itself

#

to get the interesting stuff you'll want to multiply the sine by i

#

$f(x) = \cos(x) + i \sin(x) = e^{ix}$

somber coyoteBOT
ember loom
hoary moat
#

Ahh cool..

#

so cos and i sin is an interesting even/odd decomposition.

upper karma
#

Is it 5x-28=x

#

Or am I wrong

manic anvil
#

Wrong

tropic marsh
#

help plz

honest valley
# tropic marsh

there's nothing tricky in this question, you just need to plug the numbers into the formulas for the volumes of stuff and add them all together

graceful light
#

I ended finding the base for number 1 I think it's 176.8 but I'm not sure if I'm supposed to multiply the base with Height

honest valley
# graceful light I ended finding the base for number 1 I think it's 176.8 but I'm not sure if I'm...

This video was created to help teach students in Grade 5 or 6 how to calculate the volume of a rectangular prism. This was specifically designed to be used in a classroom with the teaching acting as the facilitator, but it could also be used for home schooling or personal learning.

▶ Play video
graceful light
#

thanks i'll check it out right now

honest valley
# graceful light

i don't think the question gives you enough information to calculate the volume of the slanted prism but the volume of the prism that's standing straight up will be bigger

velvet sand
#

can someone help me solve this question

cloud stump
#

Sine 12.5

#

Nice

upper karma
#

help Q17

dark sparrow
#

no

tepid crow
dark sparrow
#

ordering others to solve it

tepid crow
silent plank
#

,w SOLVE Q17

somber coyoteBOT
tepid crow
dark sparrow
dark sparrow
#

the terms, as written, are all real

#

unless you are suggesting ||writing them as arg(3+i), arg(7+i), etc.||

tepid crow
#

isn't it just a simple telescopic series?

#

this might be more simple, never thought about it with the complex plane

tepid crow
#

the series' general term should be tan^-1(n+1) - tan^-1(n)

#

never thought about it in that way and now it seems like common sense

#

thanks hype

earnest basin
fervent valley
#

draw a right angled tri

#

I think the angle within the line of the 90 degrees is the 15 degrees

earnest basin
#

I cannot draw

waxen glen
#

I get 25/34 is it right?

cursive python
upper karma
#

but that complex plane method is great ia m now trying to understand it

tepid crow
#

True, I have never thought of it in that way too

#

Seems like the logical way to look at inverse trigonometry

wintry harbor
graceful light
#

can someone recommend a video or explain

honest valley
graceful light
#

thank you

floral imp
#

Can someone help me with this??

silent plank
#

draw a diagram

cloud stump
#

In the triangle ABC you draw BP perpendicular to AC and the median BM.

Is it a theorem that (PB)(PM)=(AP)(PC)? The textbook I use states that with no poof whatsoever

#

Or am I being really dumb and it is a very obvious thing idk

cloud stump
hallow panther
#

help pls?

honest valley
honest valley
digital rose
#

does anyone know how to solve this?

hallow panther
#

wat u ned help with

hallow panther
digital rose
#

everything bro

#

i’m totally lost

cloud stump
#

The arch is double of the inscribed angle

#

That's it

#

And the whole circle is 360 obviously

#

@digital rose

digital rose
cloud stump
#

Yes

digital rose
cloud stump
#

Uh maybe

digital rose
cloud stump
#

The radius always forms 90 degrees with the tangent line

#

Well I mean what perimeter are they even talking about

#

Like the arch and the angle thing? Tf

digital rose
#

i think it could be the arch?

#

nah it’s the angle

#

i think?

cloud stump
#

Ok so you know the formula for the lenght of cirumceference?

digital rose
#

no

#

is it pi x diameter or nah?

cloud stump
#

Yea exactly

#

So if you wanna know the lenght of an arch you are gonna have to take a fraction of that

#

So if you wanna know the lenght of arch VT you'll need to its measure in angles

digital rose
cloud stump
#

Well the radius forms 90 degrees with tangent lines

#

After that you get a quadrilateral with 3 known angles

#

The angles of a quadrilateral sum 360 degrees

#

The angle for VT is that unknown angle

digital rose
upper karma
#

Anyone need math help

vital orbit
#

anyone know how to do this

wise pawn
#

do you know how to find the midpoint of two points?

vital orbit
#

well yes, but they are K

#

so i cant yet

upper karma
#

i got it

#

want me to send a picture?

vital orbit
#

sure

#

@upper karma

upper karma
#

@vital orbit

vital orbit
#

thank you very much

elder violet
#

i have a question

#

a triangle with an angle of 30, 60, and 90
all of the triangle sides must not be a decimal number
what is the length of the 3 sides of the triangles?

#

i need this for my track piece for a game

#

it has to be proportional so that it can connect to each other

#

it kinda look like this atm

upper karma
#

@elder violet, I don’t think there is any way you can have all 3 sides of a 30, 60, 90 triangle as whole numbers. I will try to double check tho

dark sparrow
#

@elder violet why do you need all the lengths to be integers?

#

as it stands, your problem is impossible

elder violet
#

but it's actually impossible

upper karma
#

Yes, there’s no way not with this triangle

elder violet
#

closest i can get

dark sparrow
#

the sides of a triangle with 30, 60 and 90 angles are in the ratio 1 : sqrt(3) : 2

#

why can't you have non integer lengths tho

elder violet
#

well it simply that there would be a tiny tiny gap that i bothered about

#

i need the end of the track has a position which is equal to the start piece of the track

#

it somewhat works

#

but the gap

fervent valley
#

how do u do this?

silent plank
#

note that according to your graph,
b > 0 > a

#

you have identified the 2 intercepts, but haven't associated them with the correct variables

fervent valley
#

oh i see

#

I cant factorise the qyadratic above

#

wait they are asking for the line of symmetry right?

#

no idea how the ans is (4,5)

#

I used the line of symmetry formula -b/2a thats how I got 4

#

not sure abt 5

silent plank
#

plug x=4 into your function

#

to get the associated y-coordinate

earnest basin
#

Hiiii

#

I need help

nova sable
#

i need help, How do you find the perpendicular height of a cone given volume, ab and radius

storm portal
#

Wait

#

Lemme check the volume of a cone

nova sable
#

for me its 280

#

the volume

storm portal
#

ok. . . . .

#

Oh okay

#

280 = 1/3 * πr^2 * h

#

given r, you can solve for h 👍

nova sable
#

aight

#

thx

storm portal
#

np

nova sable
#

wait its that simple

#

yikes

#

maybe sleep might help

#

youre a legend

storm portal
#

XD

#

Yeah - sleep will mess you up lol

#

ty

ember loom
#

This is <AED correct?

storm portal
#

Look good to me

ember loom
#

thanks

digital rose
#

does anyone know the awnser to this today is my last day of school so plz help

storm portal
#

What shape is the cleared area?

#

Given this shape, you can use a formula to find its area

#

@digital rose

digital rose
#

rectangle?

#

@storm portal

storm portal
#

The area that the wiper covers

#

not a rectangle

#

That's the whole rear window

digital rose
#

a half circle?

storm portal
#

👍

#

So if you can find the area of this half circle, then you have your answer

#

In order to find the area, you need the formula for the half circle

digital rose
#

what is the formula for a half circle?

storm portal
#

do you know what the formula for a circle is?

digital rose
#

wait wouldnt it be pie then 12.75/2

#

for my problem

storm portal
#

what was the formula you used for the half circle?

digital rose
#

pie then radius divided by two

storm portal
#

the divided by 2 is accurate - but the formula for a circle is πr**^2**

#

so your answer for the area of the half circle is

$\frac{\pi (12.75)^2}{2}$

somber coyoteBOT
digital rose
#

that’s for a half circle right?

#

oh thanks man

storm portal
#

👍

neon hamlet
#

How would you do this?

honest valley
#

i don't have the equations memorized but once you look them up, you just put in the numbers and solve for x

#

lateral area = 100 pi = something something r
surface area = 136 pi = something something r

#

then you'll have 2 equations and 2 variables and so you can figure out what r is

#

do you know how to solve a system of equations?

honest valley
# neon hamlet

The first part of this algebra video tutorial explains how to solve systems of equations by elimination and the second part explains how to solve systems of equations by substitution with 2 variables. This tutorial contains plenty of examples and practice problems.

My Website: https://www.video-tutor.net
Patreon Donations: https://www.patr...

▶ Play video
neon hamlet
#

@honest valley I think I figured that out but do you know how I would complete this:?

#

I know I have to use system of equations here but what formula or the equation basically

honest valley
#

do you know how to calculate the volume of those shapes?

neon hamlet
#

yeah

#

but im missing information like the height and the length of the box

honest valley
neon hamlet
#

wait is that the length of the square base?

#

in the end I got 14.17

neon hamlet
#

oh wait nvm

covert rune
pure cape
#

Probably an error

upper karma
#

@covert rune do you need help proving it?

covert rune
#

Thanks for the offer, though

upper karma
#

@covert rune that is true what kind of question 😂

tropic marsh
#

help pl

trim breach
# tropic marsh

You perform the multiplication the same way as if it were two binomials: multiply each term within the trinomial by each term in the binomial.

lavish plover
#

Yo I'm online and I need help

#

It let me copy and paste it and I dont want to cheat and look up answers

#

"Find all points of intersections of the circle x2 + 2x + y2 + 4y = -1 and the line x - y = 1
Find the area of the triangle enclosed by the x - axis and the lines y = x and y = -2x + 3" I'm confused on 1 and 2

trim breach
#

The second one you should approach by finding the point of intersection between the two lines.

#

That will give you the third vertex of the triangle, and from there, you can use distance formula, then Herron’s formula.

lavish plover
#

OH

#

OH I THINK I GOT IT

#

WAIT

#

ONE SEC

#

OH OH THANK YOU SO MUCH

#

LOVE YOU FOR THAT MAN

#

BYE

#

TY

hushed seal
#

bro

#

i need someone

#

to teach me

#

sin cos and tan

#

like

#

fast

#

n

#

good

#

;-;

#

its 9:30 pm i have been studying for

#

10:30 hours

#

i just want a revision my exam is tmrw

lavish plover
#

Sin is equal to the side opposite the angle that you are conducting the functions on over the hypotenuse which is the longest side in the triangle. Cos is adjacent over hypotenuse. And tan is opposite over adjacent, which means tan is sin/cos. this can be proved with some basic algebra.

hushed seal
#

holy shit nigga

#

vc

lavish plover
#

JSJSJS I CANT

#

I'm doing a test

#

wait what grade are you in?

#

so basically

#

sin equals opposite/hypotenuse

#

so just think of it as the opposite

#

well yeah, no shit

#

its actually Sine, Cosine and Tangent

#

but its just shorten

#

tan adjacent 0 = adjacent cot opposite θ = Unit circle definition. For this definition 0 is any angle.

#

Are you on right triangles

woeful cosmos
trim breach
# woeful cosmos

Find DO, then draw OH. I think you should be able to see where to take that afterward.

woeful cosmos
#

DO is 4 in

trim breach
#

Yes.

#

Do you know what OH is?

woeful cosmos
#

no

trim breach
#

H is a point on the circumference.

#

O is the center of the circle.

woeful cosmos
#

ya

#

i dont know how far it is

trim breach
#

Therefore OH is a radius.

woeful cosmos
#

OL is 4 in

#

LP is 3 in

trim breach
#

That is correct, but you don’t necessarily need those.

#

Consider triangle ODH.

#

You said OD was 4.

#

And we know that OH is a radius.

woeful cosmos
#

yes

#

i dont know what that means though

#

that oh is a radius

trim breach
#

Well, the problem states that the radius of the circle is 7.

woeful cosmos
#

oh ya

trim breach
#

Do you know how to find DH then?

woeful cosmos
#

no

#

i sitll dont

trim breach
#

So in triangle ODH, you have:

#

Leg DO = 4

#

Hypotenuse OH = 7

#

DH is a leg, so we want to use the Pythagorean Theorem.

woeful cosmos
#

so

#

5.7

trim breach
#

Yes!

obtuse smelt
# hushed seal sin cos and tan

ayyooo idk if i am too late but i remember them like this
this is for right triangles btw
Soh- Cah-Toa

Sin = opposite/hypotenuse
Cos =adjacent/hypotenuse
Tan = opposite/adjacent

cedar kiln
#

Can someone help me on some homework?

#

for math

honest valley
acoustic jungle
#

usually when they say this they will dm you and it's actually their test.

stone tulip
#

Can someone point me in the right direction here, I’m trying to help someone on their math but I haven’t taken geometry in 8 years

silent plank
#

inscribed angle theorem

stone tulip
#

Yea I got that y is 48

#

But I don’t know where to go from there

#

Or is x just 33?

#

Inscribed angle is any that has a point on the circle?

#

Why they give so many things if you don’t need all of them Emoji_Depress

upper karma
#

MacBook?

#

seriously

stone tulip
#

Not mine I’d never use a MacBook but also who cares

tepid crow
#

The answer is given as 0

#

Sending my steps

#

Not sure how it comes out to be 0

upper karma
#

anyone know how to do this

honest valley
upper karma
upper karma
#

does it matter if you rearange (1-sin^2x) or (1-cosx) for this question?

honest valley
#

,w tanx = sinx/cosx

somber coyoteBOT
steep temple
#

can I answer this question without differentiating?

silent plank
#

yes

steep temple
#

my approach was to create another line, a normal to L

#

set the 3 equations equal to eachother and solve for the intersection

silent plank
#

consider double root / discriminant

steep temple
#

i am not sure how the discriminant is relevant here

#

it may tell me if they intersect, not where, no?

silent plank
#

for a tangent you'd want the curve to just bounce off the line

#

here you'd only want 1 place where they intersect

steep temple
#

sure

#

but what would i be taking the discriminant of?

silent plank
#

the quadratic you get when trying to determine where they intersect

steep temple
#

the k in y=3x+k tells me the y-intercept of L, no?

silent plank
#

yes, but you aren't really interested in that

steep temple
#

so if i rearrange $$ \frac{1}{3}x^2 + 8 = 3x+k$$ into $$ k = \frac{1}{3}x^2 - 3x + 8 $$

somber coyoteBOT
steep temple
#

i am not sure how this gives me the intersection

silent plank
#

basic principles of solving a system of equations

#

the solutions to this quadratic equation are the x-coordinates of the intersection points between the curve and the line

#

for a tangent, you'd want this to have 1 solution

#

consider rearranging this to general form
and solving D = 0

steep temple
#

the latter equation is already in general form, no?

silent plank
#

no

#

you want stuff = 0

steep temple
#

but then i'd have k in the quadratic?

silent plank
#

yes

steep temple
#

so c becomes (8-k)?

silent plank
#

yes

steep temple
#

i got k=5/4

#

which, after graphing, seems to be the right solution

#

thanks

steep temple
round prism
#

Can someone please help I’m timed on this and I have no idea what I’m doing

narrow plinth
#

How do i find the maximum area of a rectangle that's inscribed in a right angle triangle and one of the sides of the rectangle is on the hypotenuse

narrow plinth
#

<@&286206848099549185>

narrow plinth
#

I did

#

I've tried using some triangle similarities didn't go no where

humble pulsar
#

oh wait, side is on the hyp

narrow plinth
#

Yeah

#

This is like the last step of this one big geometry problem and i just wanna be done with it

silent plank
#

the earlier parts will probs be useful

narrow plinth
#

I know all side lenghths

karmic glade
#

Its vertices will touch the middle of the side of the triangle maybe

narrow plinth
#

Myb but how would i prove that

karmic glade
#

oh wait, no

#

its not everytime

silent plank
#

seems like this will involve similar triangles

karmic glade
#

does it look like this tho ?

narrow plinth
#

Well it should look something like that ig

tepid crow
grim rampart
#

does anyone know how to graph a right triangle on geogebra ?

pure cape
#

just graph two lines perpendicular to each other, and a slanted line intersecting those two lines

upper karma
#

How do I find tangent from specific point on plane?

dark sparrow
#

find in what sense?

#

compass and straightedge construction?

upper karma
#

so imagine line rotating from that single point and than it hits circle

#

how do I find point where it meets circle

#

its basically how to find tangent but from specific point

dark sparrow
#

again, what do you mean by "find"? do you want the coordinates of the point, or what?

upper karma
#

yes I want cordinates of point where line and circle meets

dark sparrow
#

okay

#

and i'm assuming the coordinates of the red point and the center of the circle are known? and also the radius of the circle?

upper karma
#

yes

dark sparrow
#

are you using any notation for them that i could follow?

upper karma
#

what do you mean notation? Sorry english is not my first language

dark sparrow
#

what is your first language

upper karma
#

Croatian

dark sparrow
#

okay nevermind

compact galleon
#

Oh wait I'm serbian I can help

dark sparrow
#

have you given any names to the radius and the points

upper karma
#

Lepo lepo

#

I am basically using old CAD program and I dont know how to find tangent of circle from specific point, sizes are not even important

#

they dont have function that automatically finds it

dark sparrow
#

okay so you don't have any names

#

that's fine

#

i'll write O(x_0, y_0) for the center of the circle, A(x_1, y_1) for the red point, and r for the radius

upper karma
dark sparrow
#

if we write T for the point of contact, then we must have OT = r and angle ATO = 90°

#

so AT = sqrt(AO^2 - r^2) by the Pythagorean theorem

hard arrow
# upper karma

I am not sure if this is what you want to find exactly but, i think finding the Cartesian equation is what you are after. For that matter, let (xa,ya) be the coordinates of the red point A, and let (xo, yo) be the coordinates of the circle center O, and let P with coordinates (xp,yp) be the tangent point. So, finding the Cartesian equation of AP boils down to finding two things : a point that belongs to AP ( say A for example ) and a normal vector perpendicular to AP, which in this case is vector(OP) with coordinates (xp-xo = M, yp-yo = N). So the equation is : Mx + Ny + c = 0, and as A belongs to AP, so c = - ( Mxa + Nya ). And thus, (AP) : M(x-xa) + N(y-ya) = 0 where M = xp-xo and N = yp-yo

silk patio
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You can do it without coordinates

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There is a coordinate-less construction of it

upper karma
silk patio
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Draw some lines and stuff

tropic moon
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Quick question.
So we know with the trig identities that sin^2(x) + cos^2(x) = 1
Considering that, would sin^2(2x) + cos^2(2x) = 1 work too?

upper karma
silk patio
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PK and PL are tangents

nova sable
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this isnt really directly geometry, but lets say you have a hollowed sphere filled with a carbonated drink, will the sphere be strong from the inside? (I assume so)

upper karma
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@silk patio how do you get all these other dots and lines?