rcosa thingy

[vestal owl]

idk where i went wrong, i used cos instead of sin simply cause i like using it more

[agile heart]

wtf is rcos a

[dry coyote]

Ur meant to do rcos(x-a)

So it’s pos

For a

Cos it’s pos in the thing and u just put rcos as pos when there’s a negative

[vestal owl]

i tried it with sin but it still gave the same answer

[dry coyote]

Try this

[dry coyote]

What did u get

For sinx

[verbal kiln]

That'll give him the same values as he put

[vestal owl]

the exact same answer

[dry coyote]

Yh I clocked but ur meant to do that anyways

[scarlet bolt]

You’ll get rcosa = 6 using sin

[agile heart]

Is this parametric equations

[scarlet bolt]

Trig

[vestal owl]

no its trig

[vestal owl]

hmm but how would i do it with cos?

[dry coyote]

Did u get 53.1 degrees for sin

[agile heart]

So why are we doing r cos a if it isn’t parametrics? I have never been taught this

What topic of trigonometry is this under

[vestal owl]

i got 36.9 with sin as well

[dry coyote]

well ur meant to get 53.1

[vestal owl]

how would i do it with cos

[dry coyote]

well generally if sin is first just use sinx thats the only answer i have that can satsify u atm i dont rlly kno, ive had the same q i settled on that

[vestal owl]

oh is that how it works?

then whered i go wrong for part b

[dry coyote]

well idk if u get the same answer, i can just spot a mistake

[agile heart]

What exam board is this

[dry coyote]

theres already a negative, so rsina = 3, not -3sin3x=-3

ur solving for a, not theta

[vestal owl]

edexcek

[vestal owl]

oh

[dry coyote]

ye

then u solve theta after u get a

[vestal owl]

oh okay ill try that then

[scarlet bolt]

You’ve alr done it correctly w cos

[vestal owl]

its wrong though

[scarlet bolt]

Sin and cos are complementary angles

90-36.9 = 53.1

They’re both the same

[vestal owl]

so what do i do?

[scarlet bolt]

10cos(x-36.9)=5 root 3

You’ll get the same values if you did

10sin(x+53.1) = 5 root 3

[vestal owl]

ohh i minus it instead of + it okay

[scarlet bolt]

Yeah because it flips for cos

[vestal owl]

yeah ofc

wb for the second one? would that be -18.77

[dry coyote]

i flippin said dat🥲

[vestal owl]

did you 😭

[dry coyote]

yeah

both of em

[scarlet bolt]

For b?

Nah

[vestal owl]

oh

what would b be

[scarlet bolt]

Tan^-1(3/2)

Whatever that is

Thats what a is

R = root 13

Root 13cos(3theta + tan^-1(3/2))

Then work out theta

[vestal owl]

omg

i did got that right

but i divided it by 3 cause i accidentally was working out theta instead of a 😭

hate this rcosa topic its so annoying

[scarlet bolt]

It’s calm if u write out each step clearly