#Trigonometry

185 messages ยท Page 1 of 1 (latest)

stone schooner
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i have an exam in 9 hours and this particular question is coming up so id apreciate if anyone helps me out with this

sudden pendantBOT
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  1. Wait patiently for a helper to come along.
  2. Once someone helps you, say thank you and close the thread with: ```diff
    +close
safe spindle
oblique ploverBOT
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Civil Service Pigeon

stone schooner
safe spindle
solemn cobalt
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But it says to use the tan(A+B) formula to solve this

safe spindle
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That's how you expand the LHS

solemn cobalt
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๐Ÿ‘

stone schooner
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i been trying for hours

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and i couldnt

stone schooner
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?

safe spindle
stone schooner
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cuz im getting a panic attack

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its currently 2 am and my exam is at 10

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id apreciate it if u help me do this

safe spindle
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b/c you should have the LHS is $$\frac{2\tan(A/2)}{1-\tan^2(A/2)}$$

oblique ploverBOT
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Civil Service Pigeon

stone schooner
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and then i equate this to

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=9/40

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?

safe spindle
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Mhm

rocky fossil
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it makes perfect sense up to this point

solemn cobalt
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@stone schooner do you know about trignometric ratios

stone schooner
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?

safe spindle
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tan(A)=9/40, not A=9/40

safe spindle
stone schooner
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@safe spindle can u do it on paper

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?

safe spindle
oblique ploverBOT
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Civil Service Pigeon

safe spindle
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This implies $80\tan(A/2)=9-9\tan^2(A/2)$

oblique ploverBOT
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Civil Service Pigeon

safe spindle
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From here, it's a quadratic in tan(A/2)

stone schooner
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?

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but bro

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they tell me not to use this formula

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u used this one

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they want this one

safe spindle
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Setting A=B yields the tan(2A) formula

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I just skipped the step of combining like terms

safe spindle
safe spindle
stone schooner
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a = 4/90

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and

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b = a/2

safe spindle
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What...

rocky fossil
stone schooner
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bro

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๐Ÿ˜ญ

rocky fossil
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b = -a/2

stone schooner
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we gonna fail @rocky fossil

rocky fossil
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howd we find that?

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using the formula

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tan(a+b) = tanA/2

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so a +b = a/2

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b = a/2 - a

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b = -a/2

stone schooner
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oh

rocky fossil
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he just combined the terms

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making the number positive

safe spindle
# rocky fossil b = -a/2

You do notice that the A in the given formula and the A in the tan(A)=9/40 aren't the same, right?

solemn cobalt
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Here's how to use the formula for tangent of the sum of angles, tan(A+B), to find the value of tan(A/2), given tan(A) = 9/40.

From the formula for tangent of the sum of angles, we have:

tan(A+B) = (tan(A) + tan(B)) / (1 - tan(A)tan(B))

Let's set B = A/2, so that we can use this formula to find tan(A/2). Then:

tan(A+A/2) = (tan(A) + tan(A/2)) / (1 - tan(A)tan(A/2))

We know that tan(A) = 9/40, so we can substitute this in:

tan(3A/2) = (9/40 + tan(A/2)) / (1 - 9/40 * tan(A/2))

We can solve for tan(A/2) by rearranging and simplifying:

(9/40 + tan(A/2)) / (1 - 9/40 * tan(A/2)) = tan(3A/2)

Multiplying both sides by 1 - 9/40 * tan(A/2), we get:

9/40 + tan(A/2) = (1 - 9/40 * tan(A/2)) * tan(3A/2)

Expanding the right side and collecting terms, we get:

9/40 + tan(A/2) = tan(3A/2) - 9/40 * tan(A/2) * tan(3A/2)

Rearranging and factoring out tan(A/2), we get:

tan(A/2) * (9/40 * tan(3A/2) + 1) = tan(3A/2) - 9/40

Solving for tan(A/2), we get:

tan(A/2) = (tan(3A/2) - 9/40) / (9/40 * tan(3A/2) + 1)

We can substitute the value of tan(3A/2) using the formula for tangent of the sum of angles again:

tan(3A/2) = (tan(A) + tan(A/2)) / (1 - tan(A)tan(A/2))

Substituting the value of tan(A) and simplifying, we get:

tan(3A/2) = (9/40 + tan(A/2)) / (1 - 9/40 tan(A/2))

Substituting this into the expression we derived for tan(A/2), we get:

tan(A/2) = ([(9/40 + tan(A/2)) / (1 - 9/40 tan(A/2))] - 9/40) / (9/40 * [(9/40 + tan(A/2)) / (1 - 9/40 tan(A/2))] + 1)

Simplifying, we get:

tan(A/2) = (9/31) * tan(A/2)

Therefore, tan(A/2) = 9/31.

Hence, the value of tan(A/2) is 9/31.

rocky fossil
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tbh idk waht to do after combining them

stone schooner
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love

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u

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didnt even read it yet

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but man ily

safe spindle
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,w find tan(A/2) if tan(A)=9/40

oblique ploverBOT
safe spindle
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,w tan((1/2)(arctan(9/40))

oblique ploverBOT
safe spindle
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It's wrong but suit yourself ig

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Chat gpt isn't great with math

rocky fossil
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wait a sec bro

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so after combining

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the terms

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what do we do

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remove the denominator?

stone schooner
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@solemn cobalt

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can i dm u please?

safe spindle
# rocky fossil the terms

Once you have $\frac{2\tan(A/2)}{1-\tan^2 (A/2)}=\frac{9}{40}$, yes, you can multiply both sides by the denominator to turn the equation into a quadratic

oblique ploverBOT
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Civil Service Pigeon

stone schooner
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@rocky fossil @solemn cobalt is him

rocky fossil
solemn cobalt
rocky fossil
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they dont want the value of a

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they jus want u to find tanA/2 on one side

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on its own

safe spindle
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One of the cases is rejected because of the quadrant A lies in (based off the sign of the extraneous solution)

safe spindle
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Anything else?

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Especially @stone schooner since you're the one who opened the channel

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Cause if not I'm going to close this

rocky fossil
stone schooner
rocky fossil
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to go fully through the question

stone schooner
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@solemn cobalt are ur dms open

rocky fossil
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to find tanA/2

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so we can make sure

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we did

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the right shi

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that would be great

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if not

safe spindle
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Sure, lemme know what you get

rocky fossil
solemn cobalt
rocky fossil
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i cant

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solve it

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ive tried

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omd

stone schooner
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๐Ÿ’€

rocky fossil
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$-9\tan^{2}\left(\frac{a}{2}\right)\ +80\tan\left(\frac{a}{2}\right)\ +9=0$

oblique ploverBOT
rocky fossil
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so this is the

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quadratic

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right

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?

stone schooner
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supposedly

rocky fossil
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what do i do now

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i used my ti-89

stone schooner
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how to fucking do this ๐Ÿ’€

rocky fossil
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and it cant solve it

safe spindle
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You should be able to factor it

rocky fossil
rocky fossil
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omd

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๐Ÿ˜ญ๐Ÿ˜ญ

stone schooner
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IS

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CORRECT

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HOW DID U FIND THIS

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wait why -9

rocky fossil
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yo

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i got it

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thanks

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civil

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omd

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ur

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a

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genius

safe spindle
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Are you and jusi friends?

rocky fossil
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yea

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same exam tmrw

safe spindle
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I assume you'll explain it then?

rocky fossil
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its our mock

rocky fossil
safe spindle
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๐Ÿ‘

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Good luck tmrw!

rocky fossil
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thx

safe spindle
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Get some sleep tho

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Anything else before I close this?

rocky fossil
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just a sec

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am saving the

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mathIO

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pics

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Aight

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Nun else

safe spindle
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Cheers

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+close

rocky fossil
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Have great day!