trig

[faint halo]

How to do Q4 a)

<@&791435371564892232>

[silent nova]

,rotate

[silent nova]

use sin^2 x+ cos^2 x = 1

to get everything in terms of cos

[faint halo]

Ohh ok , but then what do u do after. Bc like won't one be cos^2x and the other cosx

Ohh wait do u like sewerage them total together have like 3 cosx

[shrewd osprey]

no

it will be a quadratic in terms of cosx

so u can either sub or just factorise normally

[analog maple]

Convert the sin^2x into cos^2x

[mild adder]

its a 30 60 90

though i dont think u need to use that

u can use sine rule and pythagoras

sine rule for AD

then pythaogras for BD

then pythaogreas for DC

.

[quiet blaze]

can you go in my other post and see if what has been said is right?

my other question

[faint halo]

If it has 2sin^2x what do u do

Like do u just get 1 and minus the whole thing?

[shrewd osprey]

2sin^2x=2(1-cos^2x)=2-2cos^2x

[faint halo]

What do u do after

[shrewd osprey]

so it becomes -2cos^2x+3cosx+3=0

[faint halo]

Mhm

[shrewd osprey]

so if you prefer you could use a substitution like u=cosx to transform it into
-2u^2+3u+3=0

and just solve quadratic however

[faint halo]

Oh right

I got 2.1

And -0. Smth

[shrewd osprey]

,w solve -2u^2+3u+3=0

[feral hemlock]

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Requested by Liam-#0001

[shrewd osprey]

now resub in cosx

you have only solved in terms of u and we are trying to solve in terms of x