#geometry-and-trigonometry

1 messages · Page 323 of 1

grave thunder
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then you can change it to slope intercept form which it already is in

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i didn't want to explain the whole answer

foggy talon
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okay thank you

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yes i have the answer

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9=b

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right

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y=6x+9

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?

grave thunder
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yes

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that's your final answer

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wait

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oh wait i made aa mistake sorry

foggy talon
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okay which part was wrong

grave thunder
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don't find b that's not the technique

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its y-y1=m(x-x1)

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how did i forget that

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its the slope intercept form when one point is given

foggy talon
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oh okay so i have to put the coordinattes into the equation

grave thunder
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yes

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in x1 and x2

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sorry x1 and y1

foggy talon
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and whats the next step

grave thunder
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you will get y+3=6(x+2) right?

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that's it

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just solve it

foggy talon
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yeah

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so -3+3=6(-2+2)

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i think i messed up

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becuase i get 0=0

grave thunder
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no don't do that

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you have to get an equation not an answer

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first you changed the GIVEN question to y=mx+c form right?

foggy talon
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yes

grave thunder
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then you found m=6 right?

foggy talon
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yes

grave thunder
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then since t is parallel to u both must have their m(slope) equal. right?

foggy talon
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yes

grave thunder
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so u hase m=6

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when we are given slope of a line and one point its passing through we use formula y-y1=m(x-x1)

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you have to put m , x1, x2as given inquestion

foggy talon
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okay

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y-y1=6x-3

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-3=y1=6x-3

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?

grave thunder
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x-3 is in bracket

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why are there 2 =s?

foggy talon
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im not sure

grave thunder
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y-y1=6(x-x1)

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so y-(-3)=6(x-(-2))

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ok?

foggy talon
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yes

grave thunder
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y+3=6(x+2)

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y+3=6x+12

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y=6x+12-3

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y=6x+9

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that's the answer

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this time for sure

foggy talon
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YES its right

grave thunder
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i wanted you to understand but i made a mistake so here;s evrything

foggy talon
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yes thank you for helping

quick shale
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can someone please dm

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me

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i need help

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with a 22 question

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geo pretest

dark sparrow
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are you trying to get someone to do the test for you

foggy talon
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hey can someone check my answer

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i got y=1/2x+15/2

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my answer sounds a bit off

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please check it

grave thunder
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its correct

foggy talon
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okay thank you

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oh it was wrong

silent plank
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check your signs

kindred rapids
grave thunder
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oh yes the signs i messed that

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@kindred rapids try separating cos(a+b)

kindred rapids
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Um how do I do that in this though..?

grave thunder
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3/12+2/12

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sorry i just told you directly

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its just trial and errors

kindred rapids
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But how'd you get that? > 3/12+2/12
@grave thunder

grave thunder
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i told you trial and error

kindred rapids
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Oh..

grave thunder
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just try separating it into something that will finally give you easy answer

kindred rapids
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I'm sorry but I'm a bit confused...here

upper karma
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Remember your special angles?

kindred rapids
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Yes

upper karma
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Try to combine the special angles in such a way where their sum or difference is 5/12.

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For example, 7π/12 = 3π/12 + 4π/12.

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7π/12 = π/4 + π/3

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After you find these two specific special angles, apply the addition or subtraction identity for cosine.

kindred rapids
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Why are you saying addition or subtraction..? Could it be both that I can use..?

upper karma
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Yup!

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You can use either, depending on the special angles you found.

kindred rapids
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Okay

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Ty

upper karma
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You're welcome.

foggy talon
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can someone help with this one

kindred rapids
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Guys I don't understand how I'm going to get one of the answers in the choices in the pic I sent jn....

foggy talon
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huh

kindred rapids
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@foggy talon line s is parallel to line r therefore they have the same gradient which is -8/3....all you have to do now is substitute the points given into the equation given to find c, which is y intercept for the line s .. (the eqn is already in the form y = mx + c so it's not like you have to change it around)
Then when you find c you plug that in to the y = mx+c eqn.....m is the same as they're parallel. That's it....you'll get something looking like that => y = -8/3 (+ or -) c for your answer.

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-8/3 x **

silent plank
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try to represent 5pi/12 as a sum or difference of two special angles

kindred rapids
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So could it be pi/12 + 4pi/12...?

silent plank
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well pi/12 isn't one of the common special angles so try using something more suited to you goal

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consider 5 = 2 + 3

kindred rapids
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Okay

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Then what do I do?

silent plank
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compound angle identities

kindred rapids
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Put it into cosAcosB - sinAsinB...

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?

foggy talon
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@kindred rapids thank you

silent plank
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cos(A+B) = that
yes

kindred rapids
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Okay

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..okay I've never done any question like that and idk how to work that out when I put it into the identity

silent plank
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you should know the values of trig functions evaluated at special angles

kindred rapids
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But its 3pi/2.....not 12

silent plank
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can you show me what you have so far?

foggy talon
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@kindred rapids so the answer is only y=-8/3x

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theres no b?

kindred rapids
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I didn't work it out but ...
When I said substitute the points given in the eqn given.....you had -6 = -8/3(1) + c ..right?

foggy talon
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yes

kindred rapids
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And when you work it out...what you got?

foggy talon
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-6=-8/3+b

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add -8/3 on both sides

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10/3=b

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?

hollow raven
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remember lcd

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wait thats right but theres something missing

kindred rapids
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@foggy talon wait...

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How about you carry -8/3 on the side with -6 and work it out...from there

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So -6/1 + 8/3 = c

foggy talon
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-26/3

kindred rapids
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Yes and now put it into the eqn

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y = mx+ c

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This is for line s

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m = -8/3

foggy talon
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y=-8/3-26/3

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?

kindred rapids
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Right.
So now you can multiple through my 3 to make it look better

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Lol

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By*

foggy talon
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8.6?

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but i cant leave it as decimial

kindred rapids
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..lol no
Mutlolie through by 3 in the entire eqn
So... 3y = -8x - 26

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That's the equation for line s

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Understand?

foggy talon
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yes thank you

kindred rapids
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You're welcome:)

kindred rapids
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Okay...I really need help for this question...please, I need more explanation because I'm confused by what yall are saying to me...

Hi...can someone help with this please?
Just started trigonometry...but I'm not sure what to do here...
@kindred rapids

humble pulsar
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I dont see any question @kindred rapids

grave thunder
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you are still stuck on that

kindred rapids
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Yes because I have no idea what to do....this is like a new topic where I have no clue of anything about it.

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Listen...I looked at a video but I do not know how he got what he got
From cospi/4 , he got root2/2, how?

grave thunder
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i told you you just have to check for it one by one

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there's no trick or formula for it

humble pulsar
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$\frac{5\pi}{12} = \frac{\pi}{6} + \frac{\pi}{4}$

kindred rapids
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@humble pulsar yes I understand that

grave thunder
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you have yyour special angles check 1 by 1 to know what you can find

somber coyoteBOT
humble pulsar
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cos(pi/4) = 1/sqrt(2) since its an exact value

kindred rapids
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...how do you know that..? I'm just asking because I dont know

grave thunder
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practice youcan say

humble pulsar
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30-60-90 triangle

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pi/4 = 45 degrees, cosine is adjacent on hypotenuse from sohcahtoa

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so cos(pi/4) = x/(xsqrt(2)) = 1/sqrt(2)

grave thunder
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@kindred rapids wait do you mean you don't know values of cospi/4 and stuff or your saying you don't know how 5pi/12 was divided to pi/6 and pi/4

kindred rapids
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The values of cos pi/4

grave thunder
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well he explainedit here^?

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also for these special angles you just have to remember the table and that's all

kindred rapids
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I dont have any table

humble pulsar
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Just remember the triangles tbh, in my opinion it's easier

kindred rapids
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How can I get this table..?

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How is pi/4 ..45 degrees?

humble pulsar
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pi radians = 180 degrees

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so pi/4 = 180/4 = 45

kindred rapids
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Okay

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Makes sense

humble pulsar
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but yeah, to answer your question: break 5pi/12 into the 2 exact value angles, use the compound angle identity, then evaluate the 4 trig values you get

balmy meadow
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The radian is defined as the ratio of arclength to radius. If we choose a radius of 1, the circumference, or maximum arclength, is 2π (you may recall the circumference of a circle is C = 2πr ). Thus a 360° angle is equivalent to 2π radians.

2π/8 = π/4 just as 360°/8 = 45°

kindred rapids
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@humble pulsar okay ty

balmy meadow
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Just remember the triangles tbh, in my opinion it's easier
Seconding the triangles

humble pulsar
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np

kindred rapids
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I think I'd rather the table ....not the triangles

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Could someone Send it or it cant be sent?

humble pulsar
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just make one up tbh

kindred rapids
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Lol alright then

humble pulsar
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do sin, cos, tan for 0,30,45,60,90

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that's all the table is

balmy meadow
kindred rapids
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@balmy meadow thank you

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@humble pulsar yes i know

upper karma
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There's a unit circle pinned at this channel too

balmy meadow
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I should've checked there first. New to this server

kindred rapids
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What's that...?@upper karma

upper karma
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What's what? the unit circle?

kindred rapids
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Yes lol

upper karma
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Wow

kindred rapids
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I'm also new...so

upper karma
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Oh okay

kindred rapids
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A little clueless

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Sorry

upper karma
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I just didn't have context

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Don't be sorry

balmy meadow
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The unit circle is that circle of radius 1 I was talking about. If we take any point on the circle and draw a line to the origin, we can obtain the coordinates of that point from the angle between the radius and the principle axis

upper karma
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I have something i believe it's useful

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,tex \unitcircle

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Wait for the bot

balmy meadow
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Noted

kindred rapids
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@balmy meadow I see...

upper karma
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You'll understand it easier with something texit's gonna send

kindred rapids
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Okay

upper karma
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well, not easier but like more in depth

kindred rapids
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Alright

somber coyoteBOT
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I have just restarted and am loading myself, please wait!

upper karma
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Lol well that was unfortunate

kindred rapids
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..lol

upper karma
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Wait some more i guess

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,tex \unitcircle

kindred rapids
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Lol okay

balmy meadow
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Is TeXit normally this slow?

upper karma
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No, ig it's because it's restarting itself

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Usually when you send it, it takes like 5 seconds

kindred rapids
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Guys...what's tan 150° ?
Like how sin30° = 1/2 ....what's tan150°?

somber coyoteBOT
upper karma
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There it is

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I wrote this for beginners

kindred rapids
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Okay ty

umbral snow
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If you can get sin150 and cos150 then tan150 is immediate

upper karma
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There's tears of hours spent on that pic

kindred rapids
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Thank you...us beginners appreciate your effort to help us.

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@umbral snow well I didnt get sin150 and cos 150 so...um

balmy meadow
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There's tears of hours spent on that pic
I need to get more serious about LaTeX figures lol. Don't tell me that's using TikZ

upper karma
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It is indeed using TikZ

kindred rapids
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I'm sorry but how do I know what's tan 150° equal to?

umbral snow
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Well, can you pinpoint 150 on the unit circle?

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Use that to identify sin150 and cos150

kindred rapids
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....um well I dont know where 150 is exactly...

balmy meadow
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I like to think of it as 180° (on the opposite side of the circle) minus 30° (which we're familiar with from special triangles/that table from before)

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We may want to explain quadrants and CAST since the unit circle was only just introduced

umbral snow
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I suggest at least giving "unit circle" a quick Google.

kindred rapids
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Okay I did

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So there is 5pi/6

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But um...the answer has to contain root of something...that kind of answer

wise hornet
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not always

kindred rapids
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No...its a multiple choice lol

wise hornet
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yeah

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so you have sin150 which is 1/2

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but cos150 has roots in

balmy meadow
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Maybe it would be better to think of tan(150°) as
sin(30°)/(-cos(30°))

wise hornet
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so when you divide them to get tan150 there's also a root

balmy meadow
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The pinned unit circle is pretty helpful for this kind of thing

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Just note that the coordinates are given as (cosθ, sinθ) and tanθ = sinθ/cosθ

kindred rapids
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Cos 150 is what?

balmy meadow
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cos(150°) = -cos(30°)

umbral snow
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So you really need to be able to identify where 150 is on the unit circle.

kindred rapids
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@balmy meadow okay

umbral snow
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If you can't, I suggest googling how the unit circle works.

alpine niche
balmy meadow
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It looks good to me. I would write the numerator as x•tanα so it doesn't look like x is a part of the argument though

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I'm not super qualified. Unsure whether a helper has to check this sort of thing

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Once you've found y, what do you plan to do to solve for h? (I assume that's what you're looking for, because of the = ? )

alpine niche
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i got the formula in the first two steps

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then i got h

balmy meadow
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Well done (:

kindred rapids
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So what's the answer for that question I just sent then..?

balmy meadow
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Do you normally use this server to just obtain answers?

kindred rapids
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No..

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I normally do my own work but this is really confusing so I just asked for help here...

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I also help people when i can.

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Is that bad...? Should I stop..?

balmy meadow
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So we've worked out that there's this thing called the unit circle that's a powerful tool for figuring out the values of different trig functions. We've reasoned out that

tan(150°) = sin(150°)/cos(150°)

We can obtain the exact value of the numerator and denominator since

sin(150°) = sin(30°) = 1/2
cos(150°) = -cos(30°) = -√3/2

So tan(150°) must be

1/2 ÷ -√3/2

kindred rapids
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Yes

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I'm working it out now...

balmy meadow
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Best of luck

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General question about trig for someone with more experience. Where do the "less appreciated" functions like versine and haversine show up in math? I've only used them with spherical triangles

kindred rapids
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Wait how...is that root3/2 negative..?

wise hornet
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it is

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is there a problem

kindred rapids
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I asked how..?

wise hornet
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what's the problem

balmy meadow
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For all intents and purposes here, the root of a negative number doesn't exist. This is a negative root

wise hornet
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why can't it be negative

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what?

balmy meadow
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I think they're concerned by -√3 since it's being mistaken with √-3

wise hornet
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debatable

kindred rapids
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No...I dont understand how the - sign got there..

wise hornet
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maybe they're just concerned about possible negative distance issues etc

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it's like

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it just is

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it works

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on the unit circle, 150 degrees is to the left of the origin

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it's negative x

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does that explain anything

balmy meadow
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The negative got there because I considered the positive first quadrant with θ = 30°, and then reflected the point over the y-axis

kindred rapids
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Cos150° = - cos30° ....how?

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@balmy meadow ohh

balmy meadow
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For all intents and purposes here, the root of a negative number doesn't exist. This is a negative root
I was misinterpreting your confusion. Sorry about that. If you're curious check out imaginary numbers (:

kindred rapids
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It's okay...thank you for your help.

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Is it okay if i ask for help again...? It's okay if I shouldn't
There are alot of questions we were assigned and most of them are not what i can understand and do..

balmy meadow
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It's perfectly fine to ask for help! I'm not going to be around to answer every question (I have my own assignments to work on)

kindred rapids
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Oh I know you have things to do.... I wasnt referring to you to help me alone. Lol I was just asking generally

balmy meadow
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My main concern about directly addressing assignment questions is that you may not learn something as fully if you're simply presented with the answer. If you're not sure about whether something's allowed it's best you ask someone with more experience on this server

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I only joined the server today

kindred rapids
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Oh Alright then. Ty

opal slate
wise hornet
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the area of the bright is independent of the position of the hexagon so long as it's fully inside the circle

opal slate
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I need to count the area of the hexagon, and then subtract it from the area of the circle, its the area of the hexagon that im not sure of how to count

wise hornet
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ok

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hexagons are polygons which means they can be split up into simpler shapes

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try chopping them up a bit?

opal slate
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i know i have to split it up by making triangles

pearl lava
wise hornet
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nrly, but it's not too hard

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i think

pearl lava
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I got the perimeter as 32.3 and for area I got 47.9. Is that right?

silent plank
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you can apply properties and ratios of special triangles without explicitly using trig functions.

wise hornet
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true, ig

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just still feels like trig to me

silent plank
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yeh

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what were your exact answers?

pearl lava
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my exact answer for perimeter is 32.31693247

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and for area i got 47.91201442

green tree
silent plank
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that isn't the exact answer

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the exact answer would be irrational and consist of radicals

pearl lava
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@silent plank

silent plank
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yes

alpine niche
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hi, can anyone help me to check one trigonometry problem? it's done, it's just to check if I messed up something

distant thistle
humble pulsar
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@distant thistle isolate for sin(x), then get x using cast rule ideas

wise hornet
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that won't be enough, the solution isn't nice unless i've messed something up

humble pulsar
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you can still do cast rule

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sin(x) = -8/15
Hence x is in Quad. 3 and 4

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the principle angle is arcsin(-8/15) ~ -32 which means it's about 32 degrees

opal slate
humble pulsar
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"and the penis"

cold siren
grizzled lantern
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@cold siren idk if that helps

cold siren
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oo ty

prime gull
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does anyone know how many johnson solids there are when all the polygons of the solid have to have the same edge length?

wise hornet
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infinite

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consider prisms

prime gull
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huh, why?

wise hornet
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whadja mean why

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there's a prism for every 2d polygon

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and prisms are johnson

prime gull
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ohhhh

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so like, except for a triangle there can be any shape with any number of sides

wise hornet
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i mean even a triangle

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triangular prisms are johnson if all the edges are equal

prime gull
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oh ok thanks!

foggy talon
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can someone help me with this pls

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i cant fail this class

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my parents will kick me out

grizzled lantern
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@foggy talon no then won't

foggy talon
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i have strict parents

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my parents dont believe school is hard

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but my dad dropped out

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i tried to explain i was sad and they were like its becuase of that phone

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and they took it away

glacial dawn
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@foggy talon

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Do u still need help

foggy talon
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yes

glacial dawn
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Alright

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Are u familiar with the point-slope form of linear equations?

foggy talon
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yes y=mx+c

glacial dawn
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Nah, that’s slope-intercept form

foggy talon
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oh then what is it?

glacial dawn
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Do u understand what it is saying?

foggy talon
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oh right yes

gloomy mesa
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bro what does that mean jve been deprived of math for too long

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due to covid

glacial dawn
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Alright so

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What can you do given the info provided in the problem as it relates to point-slope form?

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Meaning

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What can u substitute in

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To get the new equation

foggy talon
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y-3=1/5(x-7)

glacial dawn
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Yup, so u got the x and y right

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And the slope too I believe

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Lol

foggy talon
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yes

glacial dawn
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So now just put it into slope-intercept form

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How would you accomplish this?

foggy talon
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im not sure of this part

glacial dawn
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K so

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What is slope intercept form?

foggy talon
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y=mx+b

glacial dawn
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Exactly

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So what is on the left side

foggy talon
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y=1/5x

glacial dawn
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Yep, u gotta isolate the y

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So try rewriting our equation like that

foggy talon
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but how do i find b?

glacial dawn
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Don’t worry abt that just yet, just isolate the y on the left side

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Lmk what u get

foggy talon
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3=1/5x

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3=1/5x+b

glacial dawn
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Try this

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y-3=1/5(x-7)

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How would u get the “y” by itself

foggy talon
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adding 3 to 7

glacial dawn
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Nono we cannot add the 3 to the 7 because the 7 is in the parentheses

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But we could just add the 3 to the other side like u said

foggy talon
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i would turn the eqution to y=1/5x-7

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so 3 plus 1/5x

upper karma
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is this correct?

glacial dawn
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Nah

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Yo bro this is being used

upper karma
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oh my b

glacial dawn
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All g

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I’ll lyk after

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So

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Rosie

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Let’s not worry abt the 1/5(x-7) yet

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Just about the y and the 3

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y-3=1/5(x-7)

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To get the 3 to the other side, like u said, we gotta add it

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What comes out on the right side when we just add the 3?

foggy talon
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1/5?

glacial dawn
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Nope, for the right side, u still gotta have the 1/5(x-7) but don’t even touch that yet

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Just the 3

foggy talon
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wait sorry do we just put it on the right

glacial dawn
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Yep

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So what does it come out to

foggy talon
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y=1/5(x-7)+3

glacial dawn
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Correct

cold siren
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can anyone who knows how to do proofs dm me? thx!

glacial dawn
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Now we can worry abt the 1/5(x-7)

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So do u know how to distribute?

foggy talon
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not really

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but i think its 1/5x-7

glacial dawn
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Close, u just forgot to multiply the 1/5 by the second term, which is -7

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In distribution, u have to multiply both terms by the factor outside the parentheses

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So what would be the result of the distribution?

foggy talon
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7/5

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?

glacial dawn
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Bingo, so what’s the result

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The first term and the second term together, I mean

foggy talon
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y=1/5x+7/5

glacial dawn
#

U forgot one thing

#

What’s the sign given to the second term in the distribution?

foggy talon
#

-7/5

glacial dawn
#

Yup

foggy talon
#

y=1/5x-7/5

glacial dawn
#

What did we add to the right side at the beginning?

foggy talon
#

3

glacial dawn
#

So now what do we have?

foggy talon
#

y=-1/5x-7/5+3

glacial dawn
#

1 mistake

#

Can u spot it

foggy talon
#

-3?

glacial dawn
#

Nope, although it does have to do with signs

#

Revisit the distribution, what were the signs on the those terms?

foggy talon
#

plus

glacial dawn
#

For which?

foggy talon
#

7/5?

#

i mean 1/5

glacial dawn
#

Yea

#

So what’s our equation

foggy talon
#

y=1/5-7/5+3

glacial dawn
#

U forgot another thing this time xD

foggy talon
#

x

#

the x

glacial dawn
#

Yup

#

So what’s our equation

foggy talon
#

is that the complete answer

glacial dawn
#

Nope

foggy talon
#

y=1/5x-7/5+3

glacial dawn
#

Alright

#

Now we gotta add like terms

#

Do u want to do this in fractions or decimals?

foggy talon
#

fractions

glacial dawn
#

Alright so which terms could we combine together

foggy talon
#

-7/5 and 3

glacial dawn
#

U got it

#

What do u get?

foggy talon
#

-7/5+15/5

glacial dawn
#

Yup

#

Just add them together now

foggy talon
#

8/5

glacial dawn
#

Correct

#

So what’s the equation we have now

foggy talon
#

y=1/5x+8/5

glacial dawn
#

And what’s the slope intercept form again?

foggy talon
#

y=mx+b

glacial dawn
#

Does it match what we have?

foggy talon
#

yes

glacial dawn
#

That’s ur answer

foggy talon
#

okay thank you for helping me

glacial dawn
#

Yea np

upper karma
#

is this correct?
Yes.

glacial dawn
#

Thx ^^

#

For answering

upper karma
#

anyone know how to do this

umbral snow
#

@upper karma
Start by squaring both sides

upper karma
#

yeah i did

umbral snow
#

Keep in mind that squaring will create false solutions

upper karma
#

i got like x+2sqrt(x)+1=x+9

umbral snow
#

Nice. Rearranging that:
√x = 4

upper karma
#

then i just square both sides again so x=16 and i just have to check?

umbral snow
#

Yeah, I suppose there's no false solutions here haha

#

x = 16 is the one you got.

upper karma
#

ty for your help

foggy talon
#

pls check my answer

stuck dragon
#

I think the slope is -2

#

the y intercept is good i think tho

foggy talon
#

are u sure

#

pls be sure

stuck dragon
#

yeah

#

ok im 100% sure

foggy talon
#

okay ty

#

pls check this one

grizzled lantern
#

@foggy talon you can check if a line goes through points by plugging them in

foggy talon
#

right but could you please check it i dont wanna mess up

grizzled lantern
#

it doesnt go through (-8,-6)

foggy talon
#

could u tell me where i went wrong

#

or the correct answer

#

pls

#

i got y=-1/4-4

#

does that work

glacial dawn
#

Rosie follow the steps i explained earlier

#

The purpose is to learn the content lol

#

Not just complete the assignment

foggy talon
#

yes i understand that but i really need to finsih quickly

#

i have alot of other work to do

#

its 8pm here

#

i dont want to stay til midnight

small dock
#

11 a. And b.

vague forge
#

when in doubt draw it out

gloomy mesa
#

yes draw

stuck dragon
#

yes

rose tulip
#

I've been taking Geo over the summer using Khan do you think it's advised to move up to Algebra 2?

#

Some of the math teachers are saying it might be hard once I get into Pre-Cal

#

What is there that i'm "missing"

hoary trellis
#

need to find area

dense egret
#

Complete the bigger square and minus the side pieces

hoary trellis
#

i got 1600 dunno if its right

dense egret
#

How u get that

hoary trellis
#

50x50 - 15x4

dense egret
#

Why is it 50x50

hoary trellis
#

isnt a square lxw

dense egret
#

But u got the corners missing

hoary trellis
#

ah

dense egret
#

So make it a square first

hoary trellis
#

3600

dense egret
#

And how u get that

hoary trellis
#

would u do 900+2500

dense egret
#

900?

hoary trellis
#

wait idid

#

15x4 = 60 then 60x60

dense egret
#

Wait I’ll show u the diagram and hopefully u can figure out

main lintel
#

Yes, focus on the big outer square, and from that remove the 4 minor edge squares.

main lintel
#

@upper karma Do you have a general idea what to do?

urban knoll
#

I think it’s either triangle or square

#

But im not 100% sure

dark sparrow
#

,rccw

#

are the angles on the outside (exterior) or the inside (interior) of the corridor formed by the parallel lines?

urban knoll
#

Exterior

somber coyoteBOT
dark sparrow
#

well there you have it

urban knoll
#

Thanks

dark sparrow
#

what have you tried so far & where are you stuck

hollow raven
#

To add on to that, what defines an equilateral triangle?

dark sparrow
#

thank you wikipedia

#

do you know what the angles are in an equilateral triangle? @random stratus

mighty wharf
slate kestrel
#

@random stratus are you still here? because if not I will just ask my question already

dark sparrow
random stratus
#

i have a question

dark sparrow
#

why did you delete your original post, cool332?

obsidian hearth
#

Hey guys

#

How to prove that M' is point of the radius ?

#

While M' = M1*M2

upper karma
#

@obsidian hearth what is the written construction

solid flower
#

Does anyone know SAS!

jagged sapphire
#

Can i get help

fickle walrus
#

angles on a straight line add to 180

#

@jagged sapphire

jagged sapphire
#

angles on a straight line add to 180
@fickle walrus sooo

#

that means

#

?

#

its 41

fickle walrus
#

yes

odd blade
#

Guys can I get hl I legit don’t understand this question

cosmic pebbleBOT
#
Rule 1

The help channels are solely for help with math, so feel free to post your question. Asking whether you can ask a question or if anyone knows about some specific topic is unnecessary, so please try to avoid questions of that nature.

jagged sapphire
#

pls snipe

grizzled lantern
#

@jagged sapphire u need help?

#

wassup?

odd blade
#

How do you do this please help

grizzled lantern
#

alright, so they are similar triangles

west basin
#

if they are similar the sides have the same ratio

jagged sapphire
#

@jagged sapphire u need help?
@grizzled lantern na got a 80

grizzled lantern
#

so what we can do is setup a proportion

#

so we can do 18/24=x/8

#

when we do that, we can cross multiply and solve

odd blade
#

So 24x=

#

144

grizzled lantern
#

exaclty

odd blade
#

So the length of yx is x=6

grizzled lantern
#

yep

odd blade
#

Thanks

grizzled lantern
#

np

pearl lava
wise hornet
#

30 is a solution

pearl lava
#

how would I find the other?

wise hornet
#

sketch the graph rq

pearl lava
wise hornet
#

yes

pearl lava
#

so is the answer pi/6 and 5 pi/6?

wise hornet
#

yes

pearl lava
#

how would I do it without graphing?

wise hornet
#

you can see sin(x) is symmetrical about pi/2, 3pi/2, -pi/2, 5pi/2, etc.

#

so sin(pi/6) = sin(pi - pi/6) = sin(5pi/6)

pearl lava
#

oh ok

cloud valve
#

How do you prove this?

#

do I simplify them

main lintel
#

I'd maybe convert cos^2x to 1-sin^2x

#

And try that route @cloud valve

cloud valve
#

does that mean that I can write cos^4x

#

as 1-sin^4x?

#

nvm I got it

#

thank you

main lintel
#

No, but cos^4x is (cos^2x)^2

cloud valve
#

yes I saw it now, i solved it

#

it is indeed 0

main lintel
#

Cool

untold peak
#

I'm terrible with trig and I have to do this workbook. do all angles in a non right angle triangle still add up to 180?

#

Sorry if this sounds stupid but math is by far my worst subject

white lichen
#

yes

untold peak
#

okay

subtle snow
#

Can someone help me with this?

#

I’m so confused

white lichen
#

what is the question asking

#

do you need to find al the angles with letters

subtle snow
#

Yes

white lichen
#

Ok which one are you on

subtle snow
#

Well I attempted to it but I got everything wrong

#

This is my work

#

How should I do it or what did I do wrong?

#

@white lichen

white lichen
#

For the first one why did you think a and b had angle measures 79

subtle snow
#

Because it has to equal 180

#

That’s what think

white lichen
#

But why did you think they had to be the same

subtle snow
#

I’m not sure

white lichen
#

Have you learned about corresponding angles

subtle snow
#

I think so but I do t remember

white lichen
#

if the horizontal lines are parallel those two angles are equal

subtle snow
#

Can you go to Vic so we can talk?

#

*vc

white lichen
#

I dont rly wanna talk rn but i can listen and write here

subtle snow
#

Ok

white lichen
#

go mathematics

#

yes

#

Yes but that doesnt mean 2 angles need to be the same

#

Try using the picture I sent to figure out what a would be

untold peak
kindred rapids
#

If tan (theta) = 4/3, what's tan2(theta) ?

wise hornet
#

i assume you mean tan^2(theta)?

#

generally, tan^2(theta) = (tan(theta))^2

#

and also sin^2(theta), cos^2(theta), sec^2(theta)... etc.

kindred rapids
#

@wise hornet no I meant tan2(theta)

wise hornet
#

tan(2theta)?

kindred rapids
#

tan2Ø <= it's like that.

wise hornet
#

ok

#

so tan(2theta)

kindred rapids
#

Ig

wise hornet
#

tan(2theta) = sin(2theta)/cos(2theta)

#

do you know those

kindred rapids
#

Yes

wise hornet
#

ok

#

so do it

#

and then if you need help expressing it in terms of tan(theta) again ask me

kindred rapids
#

What do I do? Tan(theta) is equal to 4/3 and they're asking what's tan2(theta) .....I'm not sure what to do with the sin2theta/cos2theta

wise hornet
#

so what's sin(2theta) in terms of sin(theta) and cos(theta)

#

oh sod this from now on sin(x) and cos(x)

azure laurel
wise escarp
upper karma
#

@azure laurel consider the theorem of angle sum on a triangle

azure laurel
#

I got x = 34

#

But when I add up all of the sides using that, it equals out to 160

upper karma
#

How are you getting to 34? @azure laurel

deft bear
stuck dragon
#

for y

#

since the purple lines are parallel

#

as shown with the arrows on that pair

#

and that you can view the green diagonal line as a transversal

#

you can say that measure of y=75

#

via alternate interior angles

#

for x

#

we could view it the same way but with the other transversal (the other line intersecting the 2 parallel lines)

#

this time we can say x=100

#

via corresponding angles

pearl lava
#

Can I use law of sines to figure out the side lengths?

stuck dragon
#

are u allowed to use calculators or no

pearl lava
#

yes

stuck dragon
#

oh ok

#

yeah u could find out the other 2 sides via law of sines

pearl lava
#

ok thanks

stuck dragon
#

np

azure laurel
#

I j want a rolly rolly rolly with a dab of ranch!

#

@limpid lagoon You are dogshit at aerials

main lintel
#

@deft bear you got your answer above

upper karma
#

please help!

wary wind
#

@upper karma what have you done so far? How have you approached it?

upper karma
#

I can't even think how to start

#

Its the hardest geometry question in my homework

#

I have no idea how to approach it

wary wind
#

Are you doing similar triangles rn?

upper karma
#

What you mean?

wary wind
#

What's the chapter you are doing in geometry right now?

upper karma
#

Im doing a weird cirriculum

#

chapter 2

wary wind
#

Probably review that chapter then.

To make the long story short - The idea is to use the property that base of the equilateral triangle and the straight line drawn from a mid-point of the base being parallel to each other.

upper karma
#

i read the chapter twice lol

#

I just couldnt put my finger where i could answer that question

wary wind
#

Okay, let's attack this another way then

How well versed are you with trigonometry?

upper karma
#

Yeah i know trig

#

btw this is the hardest qquestion in the hw

#

and it called a free question

#

so you could use anything

#

even outside the chapter

wary wind
#

Well, this is your homework - I would like you to think through this problem and apply your approach.

Also - stop saying "it's the hardest homework" - It's not as hard as you think it is.

#

Well anyways - what's angle of an equilateral triangle?

upper karma
#

60

silk patio
#

For alpha is less than 90 degrees can you work out the height of the triangle?

#

You know the base is always a/2 so you don’t need to worry about it

#

To work out the area you need the height

upper karma
#

hmmm

wary wind
#

I will just lay out the brief procedure that you can use to arrive at you result -

You angle alpha has three possibilities -

  1. Less than 90°
  2. Equal to 90°
  3. More than 90°

In each of these cases - you'll form an interior triangle with your equilateral triangle.

Next, your goal should be to prove that the two triangles are similar (read up on similarity criterion)

using this - find out area ratio.

#

Euler has given the other details you can play around with.

upper karma
#

yeah he said you need to work out heihght

#

@wary wind how could i find the height?

#

of the small trianlge

#

without the area?

wary wind
#

You draw the altitude for the smaller triangle in the case where your alpha is less than 90°

upper karma
#

ok so from the highest point to the base

#

that creates 2 right angle triangles

wary wind
#

Yes, you have 2 more right triangles then but that's not what we want to use the altitude for.

You want the altitude so that you are able to express your area.

upper karma
#

ok so if i draw that

#

for the small triangle

#

i get 2 right angle triangles

#

with height h

#

and base

#

1/4 a for each triangle

wintry fog
upper karma
#

which question?

kindred rapids
#

Hi...so I just need help with two questions
I had 35 in total and I did 33 but can't seem to do these two...
First it's this one ...
I've never done questions like this one so far and I'm not sure how to start...

earnest echo
#

Try expanding sin(x+20)

kindred rapids
#

Okay

#

sinx + sin20°

next jackal
#

@kindred rapids What's the identity of Sin(A+B)?

kindred rapids
#

sinAcosB+sinBcosA

next jackal
#

got a hint?

kindred rapids
#

sinx cos20° + sin20°cosx

#

But I'm not sure what to do from there

silent plank
#

it should be simpler if you apply something like cos(a) = sin(90°-a)

kindred rapids
#

I'm not sure what that is..

next jackal
#

Oh

silent plank
#

complementary property of sine and cosine

kindred rapids
#

@silent plank I looked at a video and they said something like that but I've never seen anything like before...my teacher hasn't mentioned anything like that ...

#

So I'm not sure what to do with that
But is there a way to work it with the identity ..?

next jackal
#

Sin(70-x) = Cos(x)? is it right Ramonov?

silent plank
#

not quite

#

you didn't apply the identity properly

#

there's probably a different way you could do it, but may get very messy

next jackal
silent plank
#

i didn't say sin(a) = sin(90°-a)

dark sparrow
silent plank
#

sin is indeed a magical expression /s

kindred rapids
#

So expand it..instead?

next jackal
#

Ok, I got Sin(70)Cos(x)-Sin(x)Cos(70) = Cos(x)Cos(20)-Sin(x)Sin(20)

#

@silent plank Is there a simpler way to do this?

kindred rapids
#

Is it okay if I send the other question I need help with..? It's just two questions...this and the one I'm sending now.

earnest echo
#

it should be simpler if you apply something like cos(a) = sin(90°-a)

Use this only on one side

kindred rapids
#

@earnest echo yes but I don't understand what that is...

#

Could you explain?

humble pulsar
#

The one you just posted is double angle

silent plank
#

this is applying the complementary properties of sine and cosine

earnest echo
#

Could you explain?
e.g

sin(30°)=cos (90°-30°)

silent plank
#

which you could confirm using the compound angle identities

next jackal
#

So my expansion isn't helpful?

silent plank
#

not really, no

next jackal
#

Okayy

#

I got Cos(70-x) = Sin(x+20)

kindred rapids
#

So x is 35?

silent plank
#

applying that identity you'd reach
cos(70° - x) = cos(x°)
which allows you to easily identify one of the solutions

#

x=35 is one of the solutions,
there are actually infinitely many, but is probably not expected of you based on the phrasing / level you're at

kindred rapids
#

it should be simpler if you apply something like cos(a) = sin(90°-a)
@silent plank so this....is it always 90°...?,

next jackal
#

Ok I got Cos70Cos(x)+Sin70Sin(x)=Cos(x)

silent plank
#

its called a trig identity for a reason

#

why must you feel the need to apply the compound angle identity to expand cos(70°-x)

humble pulsar
#

There are like ~40-50 identities similar to cos(a) = sin(90-a)

#

all the related-corelated

kindred rapids
#

..ohh

next jackal
#

why must you feel the need to apply the compound angle identity to expand cos(70°-x)
@silent plank Because it's a compound angle?

silent plank
#

is it not clear that you could get one of the solutions from
equating the arguments

#

(and the rest if you introduce general solutions)

next jackal
#

I didn't get you

#

what else can you do about compound angles?

silent plank
#

cos(70° - x) = cos(x)
you can get one of the solutions simply equating
70° - x with x

next jackal
#

..........

silent plank
#

cosines of the same thing are equal

next jackal
#

Okay, thanks

kindred rapids
#

Guys...I sent the other question further up in this chat...can you all help with that please?
...is it double angle ?

silent plank
#

yes

kindred rapids
#

2tanA/ 1-tan^2A
?

silent plank
#

parentheses

#

pls

brittle gyro
#

I would suggest pyth

kindred rapids
#

I did that but ...how do I get tan2(theta) instead?
@brittle gyro

#

Would tan2(theta) be 8/3?

silent plank
#

stuff in inappropriate places

#

stuff like A and theta

kindred rapids
#

What are you referring to?@silent plank

silent plank
#

how do i get tan2(theta) instead

kindred rapids
#

...I don't get it

silent plank
#

$\tan(2\theta) = \frac{2\tan(\theta)}{1 - \tan^2(\theta)}$

somber coyoteBOT
kindred rapids
#

Yes..?

silent plank
#

then sub in your tan theta

kindred rapids
#

Alright then.

#

I got -24/7

silent plank
#

looks good

kindred rapids
#

Thank you all for the help

#

I'm grateful.

next jackal
#

@silent plank can you tell me how to derive tan(2x) identity?

#

I'm unable to figure it out

silent plank
#

from sin(2x)/cos(2x)

next jackal
#

Okay, I did that

silent plank
#

then apply double angle identities

next jackal
#

but I'm getting cos^2(x)-sin^2(x) as denominator

silent plank
#

and divide the numerator and denominator by cos^2(theta)

upper karma
#

but I'm getting cos^2(x)-sin^2(x) as denominator
There are more forms to that

silent plank
#

to get everything in terms of tan(theta)

next jackal
#

and divide the numerator and denominator by cos^2(theta)
@silent plank I got 2Sin(x)Cos(x)/[Cos^2(x)-Sin^2(x)]

silent plank
#

whoops i meant x

#

not theta

next jackal
#

okay, the denominator is cos(2x) right?

silent plank
#

divide the numerator and denominator by cos^2(x)

next jackal
#

okay#

#

Yeah got it. Thanks

#

Wait if I divide it by sin^2(x), I got 2cot(x)/(Cot^2(x)-1) Is that also one of the identities?

wise hornet
#

so tan(2x) = 2cot(x)/cot^2(x)-1

#

then cot(2x) = cot^2(x)-1/2cot(x)

#

which is nicer

silent plank
#

identities can have multiple forms

high geode
#

use a right triangle to write the expression as an algebratic expression. I'm a bit lost on this

upper karma
#

Yeah so

#

Can i see what you've tried

high geode
#

i ended up getting 5/x

upper karma
#

Like the whole process

#

Because maybe the triangle is well drawn

high geode
#

well sec is hyp over adj and tan is opp over adj

upper karma
#

...

#

Does it really hurt to send a picture of the whole thing

high geode
#

I ended up with 5/x

upper karma
#

Let me see

#

I'm guessing you want me to check your answer then

high geode
#

I was totally lost at first some of it came back to me a little

upper karma
#

Yeah 5/x is correct

#

Good job

high geode
#

oh thanks

cosmic sun
#

the brightness is the ratio of a distance to point and line

#

and as you can see, a parabola emerges!

#

this is because the ratio on the parabola is going to 1, since by definition the distances between the point and line are equal

#

as such the brightness is going to be highest there

upper karma
#

got a cool unit circle acronym for y'all

#

AMERICAN STUDENTS TAKE COVER

west basin
#

lol ok

earnest echo
#

Wow

unkempt venture
#

we can j

#

Since p=IV

devout echo
#

So how do I find things like sss and sas for triangles, I didn’t understand it that much

dark sparrow
#

what do you mean by "find"

devout echo
#

Idk

#

My teacher says things so fast it’s hard for me to figure it out

dark sparrow
#

SSS and SAS (and ASA for that matter) are shorthands for triangle congruence tests

#

for example, if you can show two triangles have three pairs of matching sides (hence SSS, "side-side-side") they must necessarily be congruent

devout echo
#

Oh

dark sparrow
#

likewise if you find two pairs of matching sides and the angles in between also match (hence side-angle-side) that also gives you congruence

devout echo
#

Thanks

valid dagger
#

Can I ask for help regarding this question monkaS

#

I think ACB is 32° aswell but Im not sure how I can get ABC

west basin
#

ACB is 32

#

to get ABC subtract the two angle measurements in the triangle ABC from 180

#

since you know AB||OC you know AC bisects BAC and OAC

#

which means OAC = BAC

#

same reason ACB = ACO

silent plank
#

how are you getting ACB as 32

west basin
#

would that not be correct?

silent plank
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doesn't sound right

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there's no justification for it

west basin
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is you are given that AB||OC you cant justify it?

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idk geometry

silent plank
#

you aren't given that AO is parallel to BC,
instead you should apply stuff like angle sums / inscribed angle theorem to get <ABC first

valid dagger
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so wait ACB isn't 32°?

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So how am I supposed to find the other angle?

dusky surge
#

You can make use of OC and OA are the radii of the semicircle

tender fable
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How do I sketch a graph that is domain 3-10 inclusive, and 1-4 inclusive? I get how to do it if there is only 2 brackets but how do i do it like this?

silent plank
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do you have the exact question

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are you plotting 2 different functions on the same plane?

humble pulsar
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$x \in [3,10] \cup [1,4]$ ?

tender fable
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it is one function, It does not give the function

somber coyoteBOT
tender fable
#

Do I just plug this in?

humble pulsar
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no im confused what you're asking since the intervals you gave overlap

tender fable
#

I can just send the question if that makes it easier

humble pulsar
#

yeah that'd help

tender fable
dark sparrow
#

how convenient of you to just skip over the word "range"

tender fable
#

my bad

dark sparrow
#

anyway you could probably just mark the points (3,1) and (10,4) and connect them with a straight line segment

hybrid patrol
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whats the slope of this line

upper karma
#

Don't multipost

cosmic pebbleBOT
#
Rule 3

Stick to one channel and don't post the same question in multiple channels. Please don't ask for help in other channels if no one is responding in the one you have posted your question in.

steady bolt
#

can i get help with this?

round isle
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you know you can verify your answers by adding angles and see if they add up to 180. Like, add up angle 1, 2 and 3 and see if it equals 180 and also add angle 1 and 6 to see if the sum is 180

steady bolt
#

thank you

final zenith
#

I need to know the diagonal line in the middle and the one above that

upper karma
#

cos(25⁰) = 300/(length of diagonal line in middle)

final zenith
#

Yes i know that

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But what is the answer

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How do i get it

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25 = cos^-1 (300/x)

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What do i do now

upper karma
#

cos(25⁰) = 300/x

xcos(25⁰) = 300

x = 300/cos(25⁰)

final zenith
#

Does that work

upper karma
#

Yeah

final zenith
#

Wow i am stupid

upper karma
#

Practice makes perfect

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usually

final zenith
#

I'll have to practice then

flat viper
#

and this
pi < x < 3pi/2 and 3sinx-5cosx = 0
cos^2.x - sin^2.x = ?

flat viper
#

<@&286206848099549185>

solar slate
#

The lengths of two legs of an isosceles triangle are represented by the expressions (3x - 7) and (x + 5).

The perimeter of the triangle is 40cm.

Find the length of the base of the triangle.

Do NOT label your answer.

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<@&286206848099549185>

round isle
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the two sides will be equal since it is an isosceles triangle

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so you can find x

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use the perimeter to find the length of the base which is the remaining unknown side

upper karma
#

hi

round isle
#

hello

warm rose
#

can i get some help with this

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just an efficient method would be great

humble pulsar
#

no real efficient way that im aware of

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unless you were taught point-line distance formula

warm rose
#

i think the one most used

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would be okay

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if there is one

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i know the distance formula though

humble pulsar
#

distance or point-line distance?

warm rose
#

a lot of steps i’ve seen are complicated to me

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distance

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i’m not sure what the point line one is

humble pulsar
#

Ok then dont use it lol

warm rose
#

ok

humble pulsar
#

but the typical way is you need to find the perpendicular to the base through the other vertex